Author Topic: 1974 LS2 T/A resurrection (mechnaicals, frame, interior & TA Nats) updated 9/21  (Read 7525 times)

0 Members and 1 Guest are viewing this topic.

Offline TAKID455

  • Sr. Member
  • ***
  • Posts: 1179
  • Referrals: 0
While noticing several members with frame rail and suspension issues. I figured it would be wise to bring this project over here from TAC. I am one that does not care for double postings on sister sites, but is it apparent that some members are not switch hitters. There is a  Part 1 & 2 to this project, but since Part 1 is done (engine and driveline) and Part 2 (rear suspension and frame rail replacement) nearing completion, I'll post it as one. For though heading to Saratoga next week, I am hoping to have this car there at the show.

PS . This is for you Tommy ;)

As some are aware, I have been involved in modernizing / upgrading if you will a 1978 T/A which started out as simply performing the modifications and enjoy. This was until a friend offered a rotisserie so I wouldn’t have to lie on the cold floor. It is amassing how a simple event took a 6mo project and turned it into a 3yr total nut and bolt rebuild. I was hoping to have it done or at least driving by mid July so I could work out the bugs and attend the nations this year. Working on it a few evening and on the weekends does not allow engine time to properly make that happen so instead of going empty handed to the nations, I have decided to resurrect one of the birds I had waiting line. This is a car that I’ve had for about 2 yrs. It was parked in 1985 due to possible bearing failure and has not run since. I present the following 1 of 212 1974 4 speed Super Duty Trans Am engine and driveline rebuild.  This should provide others to view the internals of one of Pontiac’s greatest engines which scared Hemi guys went they came out.

nice factory headerlike manifolds

Big distributor hole to accept larger distributor gear

Extra bracing in the lifter galley to prevent cracking.  I guess moister entered the engine and make some rust. This cleaned up and I found no evidence of pitting or scoring in the cylinder bores. Heck, I didn’t event feel a ridge. I expected the engine to have one w/ 85k on it.

Hand w/ big round ports. All the valves moved freely. Glad to see none of the were stuck. One thing I don’t care for and I believe the engineer’s probably felt the same, but due to EPA regulations they were cornered into providing large 110/ 111cc chambers. Boo 8:1 compression ratio.

there was a tiny amount of water in the pan. Here is some milk shake on the pump

I found the cam lobes interesting in that they have a plateau for the peak as opposed to a gradual round peak as most cams that I have seen.

PROBLEM FOUND !!!   Bad #4 main bearing which subsequently hurt the surrounding rod bearings.

After some washing, all the internals cleaned up nicely.

intake – this turd is freakin heavy. The old performer intake I have is looking like an option.

The damaged bearings did score the crank good. I ‘m hoping a 0.010 to 0.020 cut will take them out.  The current plan is basically a stock rebuild with the addition of a better cam. The factory installed a ‘small’ cam to meet EPA regulations. A RA 4 style cam should
« Last Edit: September 22, 2009, 02:03:13 PM by TAKID455 »
2nd Gen Engineering
Specializing in Suspension and Driveline Performance Engineering
Custom/ Racing/ Restorations

Offline TAKID455

  • Sr. Member
  • ***
  • Posts: 1179
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #1 on: July 03, 2009, 02:21:43 AM »
proved interesting results and smiles. It is undetermined if it will be flat tappet of roller. Heads will be cleaned and new valves if needed. I’ll know more thorough plan once I hear back from the machinist mid week.

Other items such as brakes, exhaust, clutch, driveshaft, and trans will either be rebuilt or replaced. So the count down to the nats begins. Hope I can pull this off. Now SD bob’s car will have a sibling.

Progress has been made since last posting. The Carb is said to be fixable and will be tune to the engine and refinished to look like it did from the factory.  The carb had a black substance on the top of it and the fellow who is rebuilding it ( Jim Taylor of Pontiac engine building fame) stated that it was not your typical rust/ corrosion. Once apart, he noticed that the float was melted, thus concluding that the engine had been backfiring and the flames were coming though the carb. Interesting.  The engine will go back together mostly stock w/ the addition of a new cam and exhaust manifolds. I am told the originals are brittle and crack easy plus they are only 2.25” at the opening. RARE has some w/ a 2.5” opening and redesigned inside to allow a much high flow than the originals yet retain the stock appearance.  I noticed t he build date on the car is June 1974. this is pretty late in  the production for the ’74 year and I’m wondering how many SD’s were build after this or is this one of the last SD’s built? I could not find the build sheet behind the rear seat or above the gas tank. This may have been remove when one of the previous owners installed a CB and ran the wire under the rear eat into the trunk.

The agenda for this weekend was to remove the existing brake system and replace it w/ new pieces if needed. This started off good as things do but I veered of the path a tad. Since many of the brake system bolts were rusted tight, they needed a little heat to free them. This lead to freeing all the rear suspension bolts just incase it or any portion thereof needs to be removed.  Ok , no big deal. Well, the muffler was shot and since I decided the exhaust was in my way and would be replaced, why not remove this since we are here.  Some heat and cut off wheels fixed this. I did manage top save the tips. I started cleaning the one and looked not too bad.

Old system

I did plan to drain the old gas, so I removed the tank. Good thing I did as there were 2 pin holes just above the seam. Luckily, I have a good donor from a ’77 that will work for now.

I found a rusty area in the frame. Let’s pick at it. This action turned a hole into a really big hole. I will graft a solid portion from the ’77 parts car into this. Hope I can borrow someone’s plasma cutter for that job.

It’s a little bigger than pictured, but you get the point.

Another thing that continually bothered me on this car and others is surface and tiny flake rust particles that fall on you and get in your eye.  The underside looked really bad so, to see if there are any more bad spots and to make my eye free of falling debris in the future, I decide to sand and wire bush areas of rust. If undercoating or grease was present, I did not disturb it as the metal underneath it is protected. I should mention that I hate rust with a passion. Not only did I do the rear but the engine bay and front suspension as well as I figured rusty suspension and engine bay with a nice newly painted engine would look awful.




notice original primer above gas tank

Whew no more flaky rust. I got most of it anyhow. Even w/ a mask, goggles and hat, I changed ethnic groups. “Whatchu talking ‘bout Willis”

In order to prevent surface rust from returning, I sprayed the sanded areas w/ some black rustolem. I only did 1 light cost before I ran out of paint. I’ll finish it during the week. Its not exactly Pebble Beach or POCI ‘Best of Show’ standards, but it serves its purpose and looks at tad better. I thing it went from Ewwww to Eh.
Note: the camera is red bias therefore emphasized it more than the other colors. That is why the colors have a red hue to them and reds look more intense than they are.

saved the original primer for reference later.

SO, I didn’t exactly focus on the brakes, but time was spent in other areas of need. I did manage to install new rotors though. These were for the ’78 I’m doing until plans changes for that and C5 vette brakes were installed.

July 20, 2008
I had originally planed on leaving whatever grease and gook that had accumulated over the years on the car remained there.  Being that I prefer to work on clean cars, and it alleviate one item that could irritate you should something go not as planed, I decide to power washed this guy and give it its first washing in many years. It actually came out pretty good considering all things. I noted any factory makings (not many) prior to painting the bare metal areas.  Exhaust arrived from BSM exhaust and new fuel and brake lines will from Inline Tube via Texas Trans Ams should arrive any day now. With some lubrication, the parking brake cables and rear drum assemblies freed up and work well.

Sorry more blurry pictures. It doesn’t like anything but bright sun. When the flash is used, it focuses too much on the reds so when you turn the flash off, it doesn’t auto focus too well.

little update.
my machinist and I have learned a bit about the uniqueness of the SD engine. While all the major parts will interchange with other pontiac engines, just about each part is unique. the valves are a different length than typical at 4.985 and have a 45 deg seat. the stock double valve spring produce very strong seat pressures. around 300 psi at .500" lift. the rods are forged and have 7/16" bolts as opposed to the typical 3/8" bolts. Cams for low CR engines must be design specifically to obtain the best DCR. most off the shelf cams with big duration and lift are designed for 10:1 to 12:1 CR engines, not 8.4:1 for a stock SD. this engine comes to around 9:1. I cut .045 off the heads to yield 100cc (110cc stock) and upstroked the crank. the intake is machined to match the heads. I have obtained the H-O racing HC-03 cam from Ken C w/ rhodes lifters to provide low RPM vacuum. the stock SD cam has 303/313 adv duration which is decent but a crappy .401" lift w/ 1.5 ratio rockers. that is pathetic. the SD crank is the same as the 'N' 455 crank but with fillets machined in the journals. metallurgically, they are the same. the original crank was cracked, so I used an 'N' crank I had in stock. I though about using the aftermarket rods, but after consulting a few fellows that raced SD engines, I concluded that the stock rods will be sufficient for this build. the internals are all balanced. the block was cleaned to .030. the final displacement is 467ci. I should have the block and heads back next week to begin assembly. the exhaust is at the moment RARE 2.5" manifold w/ Pypes 2.5" transverse exhaust. the cam will most likely require or benefit form headers. the exhaust system is designed so I can switch between headers and manifolds. I will try cranes XRI electronic ignition conversion.  that's it for now

while this engine is not stock, it can be made stock if desired abiet w/ a little more compression. I basically wanted to see what
2nd Gen Engineering
Specializing in Suspension and Driveline Performance Engineering
Custom/ Racing/ Restorations

Offline TAKID455

  • Sr. Member
  • ***
  • Posts: 1179
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #2 on: July 03, 2009, 02:22:11 AM »
potential this engine could of had if it was build the way the engineers wished and the feds had stayed out of the way.

With the engine machine work about to be complete, I decided it was time to sandblast and clean up the parts required for the engine.

Valve covers courtesy of fellow board member. Thanks


When I removed the cap from the distributor, it looked awful. Apart it came and cleaned it all up to look nicer than it was. Since I will be using the XRI setup and a ‘’normal’ Pontiac cam, I removed the points system and big gear and saved them in box. I had an extra small gear from another project that was switched to a composite gear. The bottom of the dist. Housing where it meets the block had been corroded away in some areas. I used All Metal aluminum impregnated filler fill in the corroded areas.

Note the large and small distributor gears side-by-side


The dist. will be assembled after the housing gets detailed.

I got a call from the machinist and he stated that the #1 main cap was cracked. You have got to be kidding me I said.  I to a visit the following day with some main caps I had to see if one would line up which of course none did. I have ordered a new billet cap and the block will now have to be line bored. This engine loves to consume $$. Upon inspecting the original cap, we concluded that a force pushing the cap to the front of t he block caused the diagonal crack in the middle of the bearing race. The cap however, lined up with the block and was not shifted or out of line nor were there any marking on the back side of the cap to back up the outward pushing theory. The cap may have been like this from day 1 when it was being installed at GM. Who knows? So, to sum it up we have encountered a cracked crank, main cap, and exhaust manifold as well as pitted valves (this was sort of expected) and out-of-round rod ends from the spun bearings. Also, possible fire through the carb. I have a feeling this car did not live a pampered life.  Since the block would need additional work, I left that at the shop and picked up the heads and rotating assy.

SD porn

Heads with SI SD 45deg angle valves

Note pushrod guides protruding into the ports

SD rods w/ SRS pistons

Nothing special ‘N’ crack to replace cracked original crank

I am in the process of matching the bolt on engine components and knick knacks with the closest to original finishes using available staples I have obtained from various suppliers including eastwood. While I am aware that the final product will not be spot on compared to NOS or original, it will be close and suffice until funds and time become available so I can to a total resto on the car which will be many years from now. It’s only original once.


Got most of the parts painted. Rebuilt the distributor and installed the Crane XR-I unit. Also shimmed the smaller gear to work with the HC-03 cam. The only thing I am waiting for the block to come back from being align bored. #1 cap was cracked so I order an aftermarket one.  Maybe my the end of this month I should be able to take this guy for a its first spin since 1985.  Trans and shifter are painted and lubed, ready for action.




The shaker base is probably the next thing that I will do. It is all media blasted and will be sprayed with high build primer along with some other parts to create a nice smooth finish.

You already have one hell of a car, getting her back on the road where she belongs seems tedious but worth it.

thanks. the car overall has thrown some obsticals at me , but the engine takes the cake. In addition to what was mentioned previously, I have come to find out that one of the cam bearings is out of tolerance and will not fit the cam. these are good King bearings. several phone calls landed be at Dura-bond bearing (under Melling) company who manufactures the bearings for King. I explained the situation and they are sending me 2 new bearings free of charge which is nice. they should arrive Tuesday or so. Until then, I can only do so much. I have installed the crank, 6 pistons, and degreed the cam. I pressed the misfit bearing out and installed the cam w/ only 4 bearings. I wanted to check the cam, timing set, piston-valve clearance as well as clearance between the coils of the valves springs fully compressed with 1.65 rocker arms should I install them. these all check out good, so when I get the bearings, I should be good to go.

SD oil pump
while this little guy looks similar to a stock pump, they are different. when I took mine apart, it look messy and was iffy if it would clean up. I clean it along with a stock non SD pump. the stock pump appeared to cleaner gears inside, but when installed into the SD housing, they almost fit. the SD housing has a smaller volume inside along with inheritanly smaller gears impossibly to tell with the naked eye or even matching the gear with each other. with that in mind, I was able to cleaned the SD gears. they cleaned up rather well, actually better than the stock gears.

some pics

block after being power washed to clean any machings. oil galleys in the block and crank where rifle brushed.

crank installed. all bearings have .003-.0025" clearance. right where they should be.

clean and organized

stock 'Y' stamped SD cam vs HC-03 cam

 I have a set of RARE 2.5" manifolds that I was intending on using. However, the cam manuf and myself both agree that this cam will prefer headers. I may have located a set of ceramic hookers. the exhaust system is designed to accept either headers of manifolds so I can switch between the 2 when desired. also, the headers add a 40 HP gain over the stock manifolds and about 25-20 over the RARE manifolds...that was the main persuasion. If anybody needs a complete RARE manifold setup, I have a set I will sell.

Previously, I had the bottom of the engine almost ready to go when I found that there was an issue with the center cam bearing or block. After a few different approaches to fix the problem with no success, it was decided that it was best to strip the block down and take back to the machinist. A burr in the cam journal was the result of the misfit (not the band). Why did the original cam work? Back in the day, if there was a tight clearance, the block was align bored with the bearings installed. While, not fixing the original problem, it solved the interference issue and the day continued.  In my day, we fix the problem, not put a band aid on it. After the turkey holiday I go the block back and I was able to assemble the bottom end without any issues.

Power washing the block to remove any metal bits.

Crank installed

Some piston rods and other tid bits

Basic long block

Nice shiny parts covered in dull sheet metal

High build primer

I obtain a chip of the ‘correct’ SD engine paint. The paint supplier I had mix up the paint didn’t do the best job. It was close but a few shades to light. Could have been a result of the color camera flash? They supplied me with the raw pigments to try to adjust the color. I will say I cam very close. It just about blended into the sample chip, but when I sprayed the paint, it seemed to be a drop or two too blue. Needed a few more drops of green.  Aside from that, the paint job came out fairly decent.

2nd Gen Engineering
Specializing in Suspension and Driveline Performance Engineering
Custom/ Racing/ Restorations

Offline TAKID455

  • Sr. Member
  • ***
  • Posts: 1179
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #3 on: July 03, 2009, 02:23:09 AM »

With intake

Centerforce dual friction clutch and bellhousing along with intake bolt-ons.

Some progress. Engine being reunited with car. Now, keep in mind, the objective of this project was to get the car back on the road and fix just what is needed. While it was very tempting to tear apart and redo the engine bay, I restrained from do so do to funds and time. I’m already 2x’s over anticipated cost due to unforeseen problems, difficulties and minor plan changes. I will clean the engine area up in due time.  I will clean the wiring tomorrow before it is installed.

Transmission, linkage, long tube thingies are all installed awaiting for the new beginning.

Work continues tomorrow if it doesn’t snow too much. Hoping to have most of the fuel, spark and electric systems installed and hooked up ready for the big moment of truth.

FIRE IN THE HOLE!!!!!!!!!!!!!!!!!!!!!!
After the routine checking, priming, setting, and rechecks prior to starting an engine, combustion of air and fuel occurred.  I do not have the new exhaust installed yet, so this was straight headers. Man what an awesome sound. I didn’t run the engine too long as I don’t have the radiator installed. When I installed a new engine, I always run it for a little without the cooling system installed incase the engine needs to be removed. Just enough to get a little heat built up and to check to see that everything appears to be working correctly or at least not to cause a concern. I must say that this HC-03 cam sounds nasty. I attempted to adjust the timing to at least hold an idle while keeping the revs up to prevent can failure, and this thing does not care for low rpms.  I have the timing ball parked right now. I’ll play with it more once the cooling system is installed so I can bring the engine up to full temp.  Initial oil pressure registered just above 80 psi on the stock gauge. I guess the SD pump does pump at a higher pressure. Then again my 400 w/ a melling DS45 pump does 60 psi on initial start then drops to 40 when hot.  I have to tidy some things up, but for the most part, the engine is pretty much done. Over time, I’ll gather the ‘correct’ parts to replace the old looking (egr, zinc plated switches, rear carb vacuum tee, ect) and ‘incorrect’ appearing parts (plug wires, vacuum hoses, stickers, ect).  I had a question where some of the wires went, but figured that out. The one connecter with a black and a tan wire goes to the A/C system which did not come on this car. I guess they used the same harness. I ran though the gears to see if the rest of the driveline had any issues. None so far. So, I will say another SD is up and running and soon to be terrorizing the streets and giving me thrills.

I would like to see if anybody has any pictures of 74 SD cars’ engine bays w/ the air cleaner removed so I can get so good views of the wiring, vacuum and clip layouts.

I have been waiting to do a final Part 1 completion post which will commence after the maiden voyage and break-in, but due to weather conditions, that may be awhile.  I currently have the car just about ready to go expect for a quick carb & timing check & adjustment which I will do just before I take it out. I don’t want to have too many ‘start, run and stop’ sessions before I break-in the cam. Start the car, do a tune and go. I played with the initial carb settings and have the engine running better so I could move it in and out of the shop. I think have a total of 125 feet on the car so far.   This was done prior to the exhaust being installed so I know the fuel will need to be adjusted a little. One of the things I noticed was fuel leaking from the carb and some adjustment screws missing. I found that the fellow whom I had rebuild and restore it , so he says, did not tighten the screws that hold the top, body and base of the carb together, left out some screws and the throttle shaft is a tad loose for my liking. Needless to say I am not exactly thrilled with the job done by the fellow who is renown as a Pontiac expert by magazines, word of mouth, ect. Especially what he charged and stated what the finial product would be. This is as far as I am posting about this as I will deal with him directly. I doubt I will be using his services or referring him to anyone any time soon. Back to happy thoughts.  I had purchased a Pypes 2.5” crossflow system through a forum sponsor BSM. Other than the right over the axle tube being bent incorrectly and too short, I am happy with the system.  I contact Pypes about this issue and they sent a new piece. While they said this is not common, it has occurred. The new piece fit perfect and is visually different than the original piece. The other thing that could bother some about the system would be the short tail pipes. The tips do not stick out as far as the stock system. They end just after the rear valance.  The sound is a nice typical stock muscle car sound and a little louder than a stock factory crossflow system. I would prefer it to be quite a bit loader. It is actually quieter than my 79 T/A w/ flowmaster 50 series mufflers and a 400 engine. Although it is quite IMO, there is no restriction through the muffler aside from turbulence created from the perforations that hold the muffler packing.  The bar clamps have been replaced with band clamps for a cleaner look and labor saver if it needs to be removed or adjusted later except for the upper muffler clamps which also attach to the hangers. The tubes are very difficult to separate once the regular clamps have been tightened as they literally crimp the tubes. I snugged them just to hold the tubes in place during installation and adjustment. The air cleaner is sandblasted, primed, filled and painted. Looks good. All I need now is some decals for the valve cover and air cleaner.
Some pictures of the exhaust prior to the band clamps and new over the axle tube.

New exhaust

From the front

Fronm the rear

While I love snow, I do not like salt. If I took this car out in the salt, I would probably return with just a steering wheel and a radio knob. Hopefully. I’ll get a nice day soon.

We had some OK, but not great weather for a change, so I decided it was time for the initial shake down. I took the car out and went about 2 – 3 miles only to notice the temp climb past the 180 degree mark and not slow down 220..240..OK something is askew. Keep in mind, its about 25 degrees ambient air temperature outside. Pulled into a parking lot found coolant violently escaping the radiator cap and overflow tank. Engine is quite warm, hoses are hot, radiator is hot but not excessive, however the center of the radiator was cool.  Due to the cold air temp, then engine cooled down rather quickly. I managed to get the back to the shop after 2 more cool down periods. Today I was able to find some time to investigate the issue and long story short, the thermostat was not opening. I had another stock style t-stat that I replaced the Mr Gasket ‘High Flow” or “No Flow” in my case.   Let’s try this again.  When out for a 10 mile drive only to return with a smile and a full tank of gas. I got some rather excited appreciation/ acknowledgement from a fellow walking down the street w/ a 24 pack of bud.  He got the year correct too.  The image of the T/A driver/ fan club lives on.  I checked a few things, adjusted the timing and carb settings after that run and went out from more excitement. So far I have about 70 miles on the car so far since 1985. The speedo works now. I guess it was stuck somehow.  Of course there are a few items that I need to attend to, but nothing unexpected.  The major one is the rear suspension. It looks like this will be rebuilt soon. I have all the rubber, just need the leafs and shocks. Not sure if I will go stock or aftermarket detailed to appear stock.  PT F-body may have an order soon.  Other small items I noticed are:
Clock is not accurate. It works, but it is out of calibration.
Brake idiot light is on. E-brake is up. Possibly the switch in PV.
One tail pipe needs to be adjusted slightly
Shifter linkage needs to be fine tuned. It is not bad, but would like to see of I can adjust it better.
Need one 6x9 speaker.

The car rides very smooth aside from big bumps which result in a ‘bank/ cluck’ due to the worn out susopension. The engine is silky smooth with plenty of power up to 3k. I have not been beyond that yet. The rings need to seat. After about 100 – 150 miles, I’ll gradually increase the RPMs to about 5k until the first oil change at 500 miles. After that, I will spin the engine as far as it wants to go. I estimate around 6k. I have the rev limiter set there so I’ll need to adjust that if the engine continues to pull.  Failure to keep the revs low on a freshly bored engine could result in cracked piston rigs as they can catch on the boring hatch. I will say that this engine combo does not care to be below 1700-2000 RPM. Engine feed back tells me that there is a lot more excitement waiting to be had above 3k RPM. 

All in all, I am happy with the way it turned out so far.  The only issue I have with the engine is the paint on the center exhaust ports is burning. I have yet to find a paint that will hold up to the heat and not burn off the head in that area on any Buick, Olds or Pontiac engine. This wraps up Part 1 of this project. Part 2 will consist of rebuilding the suspension and replacing the drivers rear frame rail. Not sure when I will do this as I am turning my focus to the 78 I’ve been build for 3 yrs. In the interim, I will be driving the 74 and enjoying the trill of the SD.

Part 2
Part 2 of  this project will consist of repairing the driver’s side rear frame rail and installing new springs, shocks and bushings as the main focus. Other items including resealing rear window, headliner installation, a possible redying of the interior plastics and detailing the differential if I get ambitious. Not to deviate from the overall scope of this project, any restoration or ‘factory correct’ markings are not a high concern.  Documentation of any markings, colors, ect will be noted and photographed for later use. This is not to say that some items may evidently be restored to factory specs along the way.

About 800 miles have been added to the car since 12/31 when it first fired after a 23 year hiatus.  A few adjustments hear and there have resulted in a very thrilling and enjoyable 800 miles…well, maybe 795 enjoyable miles. I feel comfortable with the engine so I’ll increase the rev limiter to 6000 RPM. I had it set a 4500 initially. I have had the car to a couple of cruise nights and to a show never failing to draw attention and more so, people looking rather surprised to see a real SD.  I have observed what I consider to be two groups of on lookers. The first group would be a typical non car buff just out enjoying the event. This group casually glances in the direction of the car and continues on to a shinier object.  The second group consists of car buffs or those containing some sort of automotive related knowledge. These are some times amusing as they act similar to the first group, but pause and back tract to the vehicle to double check if their eyes had just played a trick and saw an illusionary  ‘ SD – 455’ decal. This is typically followed by a conversation of varying length between them & I. Moving on…..

With Saratoga and Dayton rapidly approaching, time to complete part 2 is dimishing.  What better way to get motivated to have a few newly acquainted T/A owners say ‘ I’m available today and would like to help out and learn so I can do this to my car’ add supply grub. I had met this fellow and then his son at a local cruise who caught me as I was leaving. They of course fit into the abovementioned ‘second group’. [Names are with held until permission is granted] Today’s task was to removed the donor frame rail and front leaf spring pocket from the donor section. This one was done as a practice test. Why the extra labor…practice makes perfect.

Some spot welds have been drilled. This was not as bad as I had anticipated. I did not anticipate the number of spot welds though. A good spot weld cutter is highly recommended, although a 3/8” drill bit will work. Center punching the spot welds is a must with either method.

After a couple of hours, we broke the frame rail loose via hammer and chisel followed by an air chisel after waiting about 10 minutes watching the fellow T/A owner slave over manual labor.

After a ‘bink’ here and a ‘bink’ there, success is granted and knowledge is gained.

Frame rail and pocket are both removed and cleaned. I’ll sand blast them during the week and coat the inside with an etching / anti rust coating. 

While disassembling the metal, I tried to position myself as if it were attached to the car. This worked well except for the spot welds attaching the pocket to the rocker panel lip. They are deep in the pocket preventing a straight shot with the drill. Due to time
2nd Gen Engineering
Specializing in Suspension and Driveline Performance Engineering
Custom/ Racing/ Restorations

Offline TAKID455

  • Sr. Member
  • ***
  • Posts: 1179
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #4 on: July 03, 2009, 02:23:30 AM »
considerations, I did cheat a tad here and drilled from the outside where the rocker panel would normally be and graciously used the air chisel. Depending on the condition of the one on the car will dictate whether this area will be replaces in whole or a patch. I will probably borrow a plasma cutter when I remove the one it the car for those areas.  Overall frame rail replacement is not as bad as it appears… far. Thanks for the help guys. You know who you are.

With the practice one out of the way, it is time for the one that will be used on the car. This specimen is out of a 1979 T/A. while the interchange books state the following inter change years 70-74, 75-76, 77-78, 79-81, I did not find any noticeable difference between the 79 and 74 units other than the hole on the bottom of the 74 is about 3/16” larger in diameter which is easily fix with a drill and the seat belt captured nut is in a different location.  2 spot welds and a new hole resolves that issue.  All other dimensions appear to be the same. I have not placed it on the floor yet, but the practice one from a 74 car and this one side by side appear to be dead on as far as bends, heights, curvature, and even spot welds.

After a few hours, the frame rail and spring pocket piece are removed as a single unit allowing for easier installation. Something I thought about while doing the practice one.

I will media blast these and prep them with a rust encapsulator on the hidden areas and an etching primer on the exposed areas.

The rear suspension now lies detached from its host.  Only a couple of hours resulted n this grimy ferrous mess on the shop floor.

I was able to locate the axle stamping and reveal that this is a ‘CM’ diff made on the 149th day (May 29th) during the 2nd shift built at
Detroit Gear. Car was built in 6/74. 100% numbers matching drivetrain. Hoorah!

The main reason other that a rusty frame rail that this mission is taking place is because the rear spring are assumed to be worn due to the low ride height and the way the car bottoms out easily. Some initial sights of the leafs looking a bit questionable. Notice how they appear flat or even concaved in the middle of the span.

A closer look reveals the horrid truth.

Here we see that both of the bottom leafs are cracked and the 3rd leaf is actually flat and fatigue due to rust deterioration as well as carrying the extra load of the broken leafs.  So in essence, I had 1.5 leafs at best on each side of the car supporting the weight of vehicle when. Good thing this is being done prior to any further driving.  A new kit from Dave at PT Fbody is waiting to be installed. Since the rear is out and it looks like heck, I will strip it, rebuild it and install it at a later date. The Highway friendly 2.73 geared rear will be installed for now due to the close proximity of Saratoga and Dayton on the horizon.  Once the long hauls are done, the original rear will be reinstalled. I built a 2.73 rear just for long hauls. It’s easier for me to change out the whole differential housing sans brakes (they stay on the car) than it is to switch the actual gears in the carrier. Not the best for off the line acceleration, but that is not the intent.

Been busy working on this guy trying to get it ready before Saratoga. Looks like we should be able to attend providing not other issues exist. To continue from where I left off, let’s start with the donor frame rail. I media blasted the rail along with various rear suspension parts to reveal the virgin metal. Good thing this was done as the left front leaf spring pocket had deteriorated to the extent that the side looked like swiss cheese.  This would not be pretty should it have broken on the road. Luckily I had one in decent condition on a parts car. Parts cars are great for even the minutest items. All bare metal parts were sprayed with etching primer and then semi gloss black following a satin clear coat. The frame rail was treated to some rust encapsulator on the inside and sprayed with red oxide primer for the factory look. The original primer on the underside of the car looks almost brown. Not sure if that is in fact the color or if it has simply faded/ darkened overtime and use. 

Blasted and cleaned parts:

Backing plates before


Some paint markings for you purist. Both axles has the same blue ring and orange swab

Gears look very good for 75k. Even the backlash/ play feels within spec.

Now for the fun stuff. With a fellow T/A enthusiast stopping by after work occasionally to lend a had and to gain knowledge for a future project of his, the heavily oxidized frame rail was removed with some spot weld drilling, grinding and carbide cutters. A pry bar provided final motivation for the rail to release frame the body. To make removal easier, the rail was remove in sections.  Actually, the middle of the removed section had barely any material left.  The upper part of the rail was cut just beyond where the inner frame ends. The will provide a solid mounting location for installation. The new rail will be both seam welded and plug welded to the inner rail assuring a strong connection.

Rusty turd . not too structural in current state.

Remaining spot welds were ground flush and the entire area was sanded to metal. Any signs of rust were treated with Mar-Hyde neutralizer (Rust converter) and primed.

Before the new rail could be welded, it had to fit. Since the donor was from a 79, the seat belt mount needed to be relocated. I used the original mount from the removed portion and welded it to the new rail in the stock 74 location which is further rearward than the 79. the 79 mount was also removed and filled. With all the ‘motivation’ required to remove the rails and spring pockets, it is common for some tweaking of the metal. This needs to be reformed by test fitting and comparison to the original example. A trick is to notice where the misfit appears and locate where the interference occurs. Most of the time they are different locations. It may even help to bump the floor up to assist in the mock fit. The floor will be hammered down onto the rail upon installation once the rail is tacked into place. Double metal exist in places so don’t be bashful with the body hammer as force is required to reform the area. While most of the 74’s spot weld hole coordinated with the 79’s, a few were in different locations. No biggie as long as they’re in close proximity, structural integrity will be retained.

Mock fit

Welding. Although some critiquing is required even as you are welding the rail, excessive fore should not be required as that will add unnecessary stress the metal and may cause problems in the future. No more than a slight bend or movement should be needed. Anything more should have been resolved during the mock fit.


I used a liquid metal filler (not plastic filler such as bondo) to fill in deep grinding marks and smooth some areas. This filler actually has metal intergraded with the bonding agent. It can be drilled and tapped. I would stay away from JB weld. I have used USC’s All Metal and Permatex’s Liquid Metal with favorable results. By no means should the filler be used in place of a weld. If a weld is poor, grind out the weld and rewelded it. Best to do it now than later.  Any areas that are not completely welded should be filled with weld as well. If during the grinding and course sanding stage, a weld has cracked or become thin, grind the area and reweld. This is rather serious as poor craftsmanship or knowledge during this stage could lead to highly undesirable events. A good test is to whack the rail with a non marring hammer or object and check for movement and formation of cracks.

After sanding the metal filler, the rail was sprayed with etching primer followed by a few coats of high build primer. I do not care to use plastic filler unless it is a last resort. So here we have the rail installed and primered. I will sand the nasty run along with the rail to a nice finish, although not too smooth as I still want to retain the factory look.

This was a project that somewhat intimidated me at first, but after taking slowly and accomplishing the task, I feel satisfied with the end result.

Of course, we all like to pick at things and look for trouble. While the primer was drying, I noticed something odd with the passenger side rail.

Things that make you go ‘Hummmmmm..”. I little cutting and picking revealed…

Which became…

A can of worms was opened, but with careful surgery and restraint, it can be closed and saved for a later time. The inner frame (portion connected to the leaf spring perch) has become deteriorated and thin in some areas. I was able to patch the bad areas and avoid rail replacement at this time. The inner rail was treated to the rust converter and encapsulator after a thorough grinding and sanding to remove the heavy rust. The rail should last several years at the worst until the full resto can be accomplished.  All capture nuts should be replaced with the suspension out. Some of mine had become freed (uncaptured) and others developed cracks which will lead to an uncaptured nut and many four letter words when removal is required.



Welded in place. This will be ground , sanded,ect and finished tomorrow. Hopefully on the road this weekend.

In the next installment, rear suspension installation along with following unit provided below will be discussed.

2nd Gen Engineering
Specializing in Suspension and Driveline Performance Engineering
Custom/ Racing/ Restorations

Offline Kevin

  • Adv. Member
  • ****
  • Posts: 2243
  • Kevin
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #5 on: July 03, 2009, 10:24:44 AM »
Wow man, great job. That engine looks really good, awesome! I want to see more!
1978 Pontiac Firebird Formula

Offline jphillips3333

  • Lifetime Member
  • *****
  • Posts: 4809
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #6 on: July 03, 2009, 11:10:32 AM »
That's Funny
"Even w/ a mask, goggles and hat, I changed ethnic groups."

I've got some #13 heads that I'll trade for the #16 heads ... interested?  I'm thinking no.  The engine turned out great. 

I'm actually stunned at the amount of rust and work you went to to bring this one back.  Great work.

                                 1 of 1107                     1 of 37,015                    1 of 1817

Offline y88rick

  • Lifetime Member
  • *****
  • Posts: 7708
  • f bodies suck. Don't buy one lol
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #7 on: July 03, 2009, 03:51:57 PM »
your more daring than me even though a 74 rare is the key i still wouldnt have went through that special effort to save it. i have to patch a quarter on one and that is almost asking too much as im sooooo picky yet affraid that rust would be over looked and come back to haunt me some day down the road.
Too many birds, not enough food.

Offline 4speed76

  • Sr. Member
  • ***
  • Posts: 1222
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #8 on: July 03, 2009, 04:10:24 PM »
Wow what a project. Keep us posted with more pics.  Nice work.
1976 T/A project
2009 Honda CRV
2001 Honda Civic

Offline RRR76TA

  • Ohio Firebirds
  • Adv. Member
  • ****
  • Posts: 2564
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #9 on: July 04, 2009, 07:55:52 AM »
Looks good

Offline rad400

  • Adv. Member
  • ****
  • Posts: 2102
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #10 on: July 06, 2009, 08:00:38 AM »
All I can say is awesome.
79 Trans am 400 t400 3500 stall #12 heads holley 750 vac carb. Torker II intake 3:73:1 gears 12 bolt rear.

Offline TAKID455

  • Sr. Member
  • ***
  • Posts: 1179
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #11 on: July 07, 2009, 12:47:42 AM »
Thanks for the complements. It has been a challenging yet rewarding adventure. I myself am stunned at the before and afters of the engine. I knew the rust would be an issue I would have to face. I aimed to fix the primary issues and save the rest for later. after purchasing the car, it was killing me to see something like this just sit and waste away. Besides, I too wanted to see what all the fuss was about these SD cars. without further adieu, I present the final installment of  the part/ phase of the resurrection. 

After some final touches, the driver and passenger frames are done. After priming the pass side, I sprayed undercoating over the area so it blends with the surrounding and preserves it for a while. The driver’s side was left painted for now because it looks nice. I had several people stop by the shop and could not figure out where I spliced the two together. I’m somewhat happy whit the outcome. Really wasn’t sure how it would turn out.

Frame rails

The after to compare to the before



With the nasty out of the way, it was time to install the new suspension. A while back, I purchase a kit from dave at PT-fbody. Hope they work. My only grip is that the shocks do not have boots to shield debris from the shaft. I’ll have to look around and see what is available.  The original rear will not be reinstalled at this time due to the up coming trips plans. I have a rear I built last year with 2.73 rear gears for better cruising on the highway. The original rear will be getting a full blasting and rebuild before it is installed most likely towards the end of the year.

Cleaned parts

Springs & stuff

Springs & stuff installed

I debated on detailing the drum brake internals and thought, after 50 miles, they will look like arse again. So I just washed, lubed and installed them.

Not to bog or strain the engine with 2.73 rears and to try out a new toy that I’ve wanted since I found out about them in the 90’s from Trans Am Specialties in Cherry Hill, NJ, a nice Doug Nash 5 speed was installed. No body modifications are necessary to install and the shifter is relatively close to the stock location. I did have to modify the cross member since the trans mount on the DN is 2.25” further to the rear of the car. I had a spare lying around that was modified so not to destroy the original. All that is left is to install the driveshaft and take it for a spin. The original ST-10 will be reinstalled with the original rear. Nothing wrong with it, so I will clean it, wrap it and put it aside in a safe place.

A little info on the DN unit. Doug Nash provided transmissions to GM in the 70’s & 80’s until the contract with GM ended. DN went belly up and Richmond liked the split case design and bought the design. My understanding has it that Richmond’s penny counters redesigned some shafts and whatnot consequently making the trans weaker. This is not an overdrive trans and some may believe. The final drive in 5th gear is 1:1. that same as a ST-10 or TH350. SO whats the big deal?? Instead of overdriving the gears, it has a very low 1st gear ratio. They can be 3.28, 4.06 & 4.41. This coupled with 3.08 or higher rear end gear provide good acceleration while the final drive is relatively low. Road racers used this trans when it came out because they could have the of line acceleration of low rear end gears and obtain high top end speeds for the long straights.  This unit has a 4.06 1st ratio which is a tad low. Eventually I will change it out to 3.28. With the 4.06 1st and the 2.73 rear, it will like having a 4.56 with the stock ST-10. Again, rather quick, but it gets the car rolling and does not strain the engine.

Cleaned & installed

This concludes Part 2 of this resurrection project, san for a drivability update. Next project will consist of front bumper replacement, spoiler paint and installation & interior redye ready by the end of August. However, my focus will switch back to my 78 as the 74 keeps interrupting its progress. Have to keep a balance to prevent jealousy amongst stablemates.
2nd Gen Engineering
Specializing in Suspension and Driveline Performance Engineering
Custom/ Racing/ Restorations

Offline T/A Tommy

  • Sr. Member
  • ***
  • Posts: 595
  • T/A
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #12 on: July 19, 2009, 12:46:11 PM »
Man Larry i cant believe how good your frame raill came out. Now since you guys have the skills to get it done, there should be NO reason that you cant do mine ;D Let me know when you want me to bring it down ;D LOL Looks very good!!!
My dad told me that your car got more attention then everyone elses. Which i think is great, Cause you and the car deserve it!
Returning from Flordia wednesday. Looking forward to seeing you soon!



1978 L78 Y88 Gold Edition
1978 L80 Y88 Gold Edition

Offline limey

  • Sr. Member
  • ***
  • Posts: 671
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #13 on: July 19, 2009, 01:26:40 PM »
All I can say is "WOW", thanks for all the pictures.  I can't get over how bad those springs were!  Great thread, keep us updated :)
79 Heritage Brown, 400 4spd, #'s matching. 1 of 2917.

Offline bigty88

  • Member
  • **
  • Posts: 331
  • 1978 SE Y88
  • Referrals: 0
Re: 1974 LS2 T/A resurrection (drivetrain, suspension and frame work)
« Reply #14 on: July 19, 2009, 01:58:54 PM »
Great thread Larry.  I win the bet ;D ;D ;D Gotta start gearing up for the NATS. Paging Dr. Larry...Paging Dr. Larry...She wants those implants done! :o