Hitman's Pontiac Trans Am Forum
Trans Am Information => Trans Am Tech => DriveTrain => Topic started by: raypfaff on March 12, 2013, 04:03:57 PM
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Hello all!
First would like to say thank you for taking the time to read. I've been a fan of the various pages on this website since I got my baby in 2011 and now I'm looking to ask the community directly for some input. Here is my situation.
I have a 1978 W72 Trans AM. I received her fully stock and was able to verify this by matching numbers and confirming options that were listed on the build sheet the previous owner was wise enough to have laminated and kept with the car. This past fall I had done some exhaust and carburetor upgrades after my Qjet started to fail and I noticed the smell of exhaust was choking me out in the cabin of the car. I replaced the Qjet, intake/exhaust manifolds and exhaust with aftermarket parts. To be more precise I had installed Edelbrock Thunder Series AVS Carburetors 1806, Edelbrock 2156 - Edelbrock Performer Intake Manifolds, Pypes Performance Exhaust SGF11R - Pypes Race Pro Dual Exhaust Systems and set of Flowtech 31170FLT - Flowtech Headers. I removed the smog pump and my new exhaust setup deleted the CAT and gave me a x-pipe with true dual exhaust.
I had initially done this for necessity and the goal of having the Qjet redone and the original manifold cleaned up and put into storage. I wanted to lighten the load under the hood and figured if I ever want to start to add power to Mumbles (that's my buddy's name) locking up solid breathing and using those recommended parts would be a great start. I was told the deleting of the smog tech/CAT, opening the secondaries and adding of the headers along with the overall weight difference would give me a gain of somewhere around 40+ hp. Conservatively I would like to think as she sits right now she has 250HP, so say a 30hp bump from her factory configuration.
I want to begin my next stage and increase torque and give additional HP in accordance to the torque. I have been told to consider aftermarket heads with corresponding cam such as Edelbrock 350-60579 cylinder heads and a matching cam for the combination 350-2157. This advice came from JEGS to really up the HP. Summit on the other had told me to go with the COMP Cams High Energy Cam and Lifter Kits K51-232-3 and have my existing heads worked on.
I've been reading through both Jim Hand's How to Build Max Performance Pontiac V-8's and Rocky Rotella's How to Rebuild Pontiac V-8's. So I know for a fact my goal is torque (this car will be a street/highway fiend and not see the strip) so I would assume my ideal RPM peak range would fall in the area of 55-75 mph. I would love to see this car not only be quick off the line and give that true muscle feel the later '70 somethings were missing but want to make sure I do right by the car and give it a setup that will allow it run appropriately on pump gas and give it the components needed to last under street and highway driving conditions.
So this is where I am at, I hope you don't mind the length of the post just wanted to let you all see what the story is and I'm grateful for the read and can't wait to hear what you think in regards to what approach I should take, what my goal torque/HP outputs should be and of course general comments.
Thanks in advance
Best
- Ray
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Ok how old is the book you are referring to? Lots has changed since these books were written mostly in the 80s and 90s.
As Far as Rocky goes, I would trust him with ANYTHING relating to these wonderful Cars!
Personally I wouldn't take Jegs or Summits advice on something as Critical as Heads, or Cam choice.
Do you have a budget or specific number you are looking for, or how much work you want to do as far as internally if necessary?
You will definitely get some feedback from some sucessful Poncho owners on here so be Open to there suggestions and tailor them to fit your needs!
Make a list and estimate what you are looking to spend on each.
Top of my list if I was doing it over would be aluminum heads and a roller cam setup, and those might both fit your needs?!
Good luck and ask away!
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sounds like the changes you have made are a good start to your goal. heads and cam would be the next steps
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If you'd like to keep a low cost headers, I'd suggest the KRE D-Port aluminum heads. They flow just as well as the Edelbrock Heads and don't require the expensive Round Port headers/manifolds. For a cam choice, try to keep the lift under .600 for a street car and as for the duration something around a 240-250 with a 113 LSA would do you good.
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I would set a power goal and budget first- that way you're working on a goal that looks at the whole car, not just the engine.
Geno
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^Yup Always set a Budget, Even tho you know you won't keep it! ::) Still a good starting point!
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Hello Everyone!
Thank you all for the replies so far. I guess as far as a budget and power goals I was hoping to get a better understanding of what I should be looking at. Initially I was under the assumption I would be looking at the Edelbrock Dport heads at $1,000 plus a piece just so I can produce the horse power. Which is a bit crazy but I figured that's just how it is. Everyone I spoke with up to that point including Butler Performance was telling me with either the high end aluminum heads or extensive reworking of the 400's "6x" heads would easily yield 400+ HP with an appropriate CAM that could still guzzle up pump gas. Jumping from 220HP to 400+HP sounds great for bragging but after the reading I've done I know for a street car its ALL about the torque. I think my goal (which hopefully you all can help me out with figuring output numbers) would be to get ideal torque with whatever level of HP would be needed but wouldn't be excessive and would allow for as much fuel efficiency as possible for the street setup I'm trying to get. I don't know anything about racing these cars so maybe 400+ is a decent start for a strip run but a complete waste for the streets, maybe it is ideal? I think I'm still trying to figure that part out.
I was initially saving assuming the heads would run $2,250 and the CAM and misc. would bump my parts to $2,600. Of course if I can go lower I would gladly pay less haha. Which would only help with my project after which will focus on replacing the worn down suspension parts (I'll be asking about that later). Hey if you can bogey and move you need the handling, no?
Also thank you for the suggestion Chuckles I will give Kauffman a call this afternoon or tomorrow to see which CC options they'd recommend for their KRE D-Port aluminum heads.
Can't wait to hear what you guys think my goal should be for HP and torque. I think that will really help put into perspective what my goal should be for parts and budget.
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Can't wait to hear what you guys think my goal should be for HP and torque. I think that will really help put into perspective what my goal should be for parts and budget.
If I may be so bold....you need to set those goals, not us. If we picked 280HP and you were hoping for 400HP then the parts, and expectations are going to be different.
To give you an idea, my 469 build is 377/477 according to desktop dyno. I have about $4k into this engine between parts and machine work. The only "aftermarket" parts on it are the Edelbrock Performer RPM intake and Holley 3130 carb. I used stock heads, stock crank, etc. I can pin you to my seat if I want. It's also built to allow me to continue using my vacuum brakes and a/c.
So pick your goals and the guys, and Geno (72blackbird) especially - I'd call him a guru, can help you from there.
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Hey Brian, I see what you are saying. The Input is definitely appreciate. Okay, so I think I would like to see 350-375 HP and 450-475 torque. Assuming those kind of numbers line up and would work together. The car came with A/C and power steering and I plan on having them put back in. Does that help?
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Ray,
I get approached by more than a few would-be customers who want to do the same thing you want- they want to basically do a head/ cam upgrade on their 400 or 403 shortblock and make around 350-400 hp and 450 ft-lbs. This type of work typically costs around $2500-3k, and while it is possible on a shortblock that has good compression I generally recommend against it. Why? You might think your engine is in good condition, but the new parts will reveal any wear on parts like rings or bearings, put added stress on them, and not give the longevity and consistent performance a fresh shortblock would deliver. It's hard to say when your newfound power would fade (depends on the mileage and overall condition of the shortblock), but when it does you will not be happy, and be looking for a refund or the mechanic to make repairs to restore the power. If you can live with this "temporary" power upgrade then a head/ cam upgrade should be enough (for now-lol).
As far as head choice goes, 350-400 hp can be easily attained with ported iron heads. Cost to go through a set of iron heads varies from state to state, but here in Socal it's not cheap- my customers spend around $1200-1500 to get a set of heads ported, port-matched, machined, and fitted with stainless 2.11/1.77 valves. A set of stock aluminum heads only cost $500-600 more, so alot just end up going with the latter. Aluminum heads also flow around 260-270 cfm out-of-the- box, so they end up being a much better value in the long run. Stock KRE D-ports or round-port e-heads will make around 450-500 hp with the right cam, so it all depends where your power goal is at. Again, putting fresh heads on a tired shortblock is almost a guarantee for disappointment down the road, so think about rebuilding the shortblock, as it is the foundation of your engine.
Geno
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Are you sure you have a Pontiac 400? I don't believe it would of ever had a smog pump on it.
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Engine has been confirmed as a 400, perhaps it just never had the pump it was my understanding all the later 70 models had those components. I guess that was my mistake. When I had the exhaust done I asked to have the smog tech deleted. Engine is a 400 and I'll get the numbers on the block this weekend.
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Okay cool, just thinking because they never made a 400 with the smog pump, it was only made to pass federal emissions testing, not California's.
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Hello everyone, it's been a while but after an unfortunate death in the family and needing to take a few weeks to get family matters in order I have an update. After several failed attempts to locate the 400 casting numbers I noticed something was off. The paint was flaking at the bottom if the block after scrubbing and cleaning I noticed the block was red underneath. I began to assume it was a chevy block. I was unable to find the vin and casting numbers but found the following numbers. Right under the cylinder cover on the passenger side toward the front of the engine the numbers "J205" and on the bottom if the engine the following 2 sets of numbers. On the passenger side "GM2 D N" and the driver side "350". I am deeply confused at this point. I guess it's a chevy 350? But I thought the 350 was strictly a V6? I opened the cylinder lids and this engine is a V8... Does anyone have any input?
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Can you take a picture of the motor?
Pontiac made a 350 v8, but so did Chevy. The Pontiac 350 was made from 68-77, so based on the other number (j205 date code Oct 20 1975) it sounds like a 1975 Pontiac 350.
Red paint is odd, maybe its a primer coat.
If it was a Chevy you would be able to tell by a few ways, such as the starter on the passenger side, intake has no open pocket between the intake and motor (no valley pan), distributor straight up (pontiac at a slight angle), etc...
Not the end of the world if its a 350 Pontiac, its part of the 400/455 family and use many of the same parts.
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Hi Angelo, here are the pictures I took yesterday. Once I get home from work I'll check the back of the block behind the 8th cylinder for the casting code. These are the photos I have. The paint is confusing and it was my understanding pontiac's ha the dipstick coming up to the front from the passenger side like in the photos. Let me know what you think.
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No need for further pictures, the last picture shows a good view of the head, definitely a Pontiac motor. Based on the date code, it's not original to the car. This all makes sense now, a 75 Pontiac 350 may have had a smog pump depending on what car it came out of.
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Okay, Great! Angelo thanks for the info I really appreciate it. How weird is it someone would paint it red and then paint it back to the pontiac blue? Its a real bummer the engine turned out to not be original motor. I was pretty happy thinking I bought an all original east coast survivor with the original order form laminated. Still glad it is in fact a Pontiac engine and I don't need to go behind the block to pull the block number right away. I know there are 2 block numbers for '75 350s. an early and late one. I'll get the number off the block this week for sure to confirm which I have but I guess now my question is... does this change anything? I know the 400 '78 had more torque and was set for 220hp (with the WS6/W72) and I was going to need D port heads for my plans. Anyone familiar with the 350 blocks and can shed some light in a direction I may need to go in now? Goals torque 375-400, HP 300-350 if possible.
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This changes things some, I'll leave it to engine building experts from this forum to go into detail and suggestions, but I know as recently as last year there was an article about a Pontiac 350 build up in High Performance Pontiac magazine, so there are options. From what you've had done so far, I think getting your quadrajet rebuilt and getting the distributor curve re-done now that the engine can breath better will help things.
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Canadian export vehicles had orange engine paint, if it look original, wild guess though.
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That would be something. My East coast T/A from PA having a replacer Canadian 350. Wild to think about. More importunely though is a 350 worth sinking money into for my power goals? I know a lot of people are saying look for a 400/450. A friend of mine showed me a bunch of 400/450s he came across in his google search and the range seems to go from 3,500 to over 5,500 for a rebuilt engine. With Aluminum heads and a cam I am assuming I'll end up spending close to 3,000 for parts if I redo the 350. Anyone have an input on whether to throw money at this motor or rather to save a bit and go for a rebuilt engine? If so anyone have a recommended reliable company or someone they know? I have a few links so far would even like to get an assessment if any of these places seem legitimate.
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I just finished the build of my 79 TA 403. i went with a mondello setup. mondello in california specialize in olds motor. i went with the mondello aluminum heads which they paired up with a matching cam, roller rockers and comes with higher aluminum valve cover. i believe the cost was 2600.00 but you will need to install an electric fuel pump. the mondello heads are 75cc which is better than the edlebrock heads at 77cc.
added a performer manifold with holly 770 carb. 2400 stall converter and 3.73 gears. bored .025 over with flat top pistons added headers with super 44 flow master exhaust. upgraded with msd 10,000 coil. just had a dino completed at premier performace and i came in at 431 hp. very happy and the power differance from 185 hp to 431 hp is un believable.
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More importunely though is a 350 worth sinking money into for my power goals? I know a lot of people are saying look for a 400/450. A friend of mine showed me a bunch of 400/450s he came across in his google search and the range seems to go from 3,500 to over 5,500 for a rebuilt engine. With Aluminum heads and a cam I am assuming I'll end up spending close to 3,000 for parts if I redo the 350. Anyone have an input on whether to throw money at this motor or rather to save a bit and go for a rebuilt engine? If so anyone have a recommended reliable company or someone they know? I have a few links so far would even like to get an assessment if any of these places seem legitimate.
Bolting on aluminum heads and installing a hotter cam will definitely wake up a 350P, but won't address worn rings or the fact the bottom end still has cast rods, a real liability and potential point of failure in any Pontiac V-8. IMO it's better to start with a 400 or 455 and start fresh, since it costs the same to build all three engines but the larger you go the more power you'll make. All of the well known Pontiac engine builders sell long blocks or crate engines, but be prepared to pay a premium vs. using a local builder. A healthy 400 or 455 can be built with forged pistons and rods and the factory crank for around $3500-4500 (iron heads- more of course for aluminum). Spend the extra money for balancing and honing with a torque plate- these are steps that no good engine builder skips.
If you decide to take this route, you'll need to set a budget, establish how much power you'd like to have, get a parts list going and then gather the parts for your build. Core costs vary from state to state, but internal parts can be sourced online.
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If she runs strong, test compression and it's within spec and you don't have any leaks or anything, I would just get the quadrajet rebuilt and getting the distributor curve re-done. Find out what quadrajet you have currently, it may be a great carb for a future 400/455 as well.
If you do swap out the motor, before you do the swap take video of your 350 running, then video testing each cylinder with a compression tester. When you go to sell it, show the buyer the videos and the compression results, you can easily sell the engine for 2x it's worth having this information, provided the tests and video show a strong runner.
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Hello All Happy Memorial Day!
Okay, so here is my update along with some Qs. I took the info from Geno and Angelo did a little research and I think I found a great situation to get a 1970 455 or a 1971 400. Did some research and came across a company called S & J Engines in Washington. They 'remanufacture' blocks and look to sell them. The work listed as done on their cores include:
Installed precision milled cylinder head(s)
Installed Valve train: new valves, new valve seals, new valve seating
Leak tested Heads & Block
Milled Cylinder Head/s
New Main Bearings
New Oil Pump
New Pistons
New Rod Bearings
New Seals & Gaskets
New Timing Belt
Each block comes with a 7 year 100,000 mile warranty and even has trade in for your current core. Needless to say sounds great to me. Question being has anyone dealt with them before? Also if I do go this route what else should I be asking about their process and cores?
I want to go with the 455 but was wondering if there is anything I should know about compatibility of a 1970 455 and the setup of the 1978 T/A. For example:
Are the motor mounts the same?
Engine location?
Would my existing timing cover (off the 350) fit the 455?
Could I use the harmonic balancer or would I need a new one?
Flywheel?
Bolt to transmission a straight forward swap?
Any parts I haven't thought of that would need to be changed out for the 455?
Thanks for reading everyone I really appreciate all the advice and can't wait to get this block upgrade going.
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I've never dealt with S & J, but I'm sure they get some business with a 7 year/ 100k mi. warranty. Sounds like a nice warranty, but unless you're local to them you'll have to eat the cost of shipping a defective engine back to them- not a cheap or easy thing to do. I'd rather have a crate engine from a well known Pontiac builder or the build from a local build with a good reputation and current references- much better than a piece of paper.
As far as cores go I do know that if you don't have a 455 core to exchange for a rebuilt 455 they will charge you- 455's are somewhat rarer than 400's, being built only from 1970-1976, so expect to pay more for a 455 than a 400. I think they also have a local core service to save on shipping costs.
I'm not sure about the 70 9799140 455, but I do know the 71-74 485428 455's and 75-76 500813 455's have 5 mounting holes per side, and will bolt into a 76-81 F-body chassis with no mods. Your 350P timing cover will bolt on a 455 with no mods, but I would forget about trying to re-use your harmonic balancer- a 30+ year-old balancer can fail without notice due to the brittleness of the elastomer between the hub and outer ring. Get a new GM, Pioneer, or Professional Products balancer- these are all inexpensive and a must for any performance engine. Other upgrades that are also worth the expense are forged pistons and rods, as well as having the rotating assembly balanced- a 455 has much higher piston speeds than a 400 due to the long stroke crank and the factory cast rods are subjected to much higher loads at speed. So many 455 owners claim they don't race, but one thing leads to another and the next thing you know those cast rods are getting tossed out the side of the block or through the oil pan- a set of 5140 replacement rods are also very inexpensive, around $240/set. I would also plan on beefing up your trans- the 455 will bolt up to it, but anything built for a 350P isn't strong enough to handle the torque of a hi-po 455, at least not for long.
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It's essentially a refurbished stock motor, most likely reusing parts that pass visual inspection. If you plan on running it beyond stock, I would not waste your time on refurbished short block. More than likely you will still need to pull it apart and put a modern rear seal on it, either a Viton 2 piece or a BestGasket "graphtite" rope seal so it doesn't leak.
Depending on the year 350P you have, your flywheel may not line up, I think either 75 or 76+ they changed the size of the register for the flywheel on the crankshaft. You will have this problem no matter what, a good engine builder is going to use a crank that has the more popular (older) flywheel register size.
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Geno and Angelo thanks for the replies. I heeded your warnings and placed and call to pull up more information. After speaking with one of their reps I confirmed they replace the harmonic balancer and flex blade. They also replace the rear seal. He said all internal components going in are new. The pistons and rods are cast but are all new from Keith Black and are silicon treated. He said he believes if I made the request upon ordering they could probably get forged ones for me instead. They stick with cast to remanufacture the specs to as close to OEM as possible while still modernizing as much as possible. He gave the example of the silicon treatment and using hard seals for modern gas. Their warranty covers labor up to $1,200 in labor and they pick up shipping cost if you go with their premium warranty for a minimal difference in cost. They seem on the up and up.
The cam they use is an Elgin E980P with specs of
Lift: .444/.466
Duration: 288/298
Duration @ .050": 214/224
Lobe Separation: 112 LC
They have other options upon request, not sure if those would be ideal specs for looking to use the 455 and maintain a certain level of street ability. Thought you guys might have thoughts about that.
As far as my trans goes I had the shop confirm it as the original so it was designed for the power of the 400. Do you think its best to replace or could it be modified to better suit a 455?
You guys are great! Thanks for everything thus far.
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Hey there, I just got a rebuilt 400 from them. (Long block) I sprung for the 7 year warranty- The motor will go in the car in the next month or so. Right now, I just want reliability - plus I am having AC installed on my car. The shipping isn't a huge issue because they have a deal worked out with a shipping company- it cost 150 bucks to have my motor delivered from them to me here in Miami. I will let you know how it goes- I got the cam upgrade, plus I had them put in Clevite bearings, as this was recommended by my shop. (TA Specialties) Any questions. just ask :)
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That Elgin E980P cam sounds exactly like my Crower 60918 cam. Similar to the 068 HO cam with a lot more lift.
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The pistons and rods are cast but are all new from Keith Black and are silicon treated. He said he believes if I made the request upon ordering they could probably get forged ones for me instead.
The cam they use is an Elgin E980P with specs of
Lift: .444/.466
Duration: 288/298
Duration @ .050": 214/224
Lobe Separation: 112 LC
They have other options upon request, not sure if those would be ideal specs for looking to use the 455 and maintain a certain level of street ability. Thought you guys might have thoughts about that.
I would forget about using KB hypereutectic pistons- their durability when facing detonation is marginal at best and the $100-125 cost savings vs. using a forged Sealed Power piston isn't worth the trade off.
I had a customer insist on using KB hypers on his 389 build to save time (I won't build any engine without forged rods, so a set of 5140 I-beams did go into the engine). This engine was capped with a set of no. 11's, so SCR was a mild 8.7:1, and the cam used was a Crower 60240. I did tell him this engine should be fed 89-91 octane, but he tried to run it on 87 and had the timing set to 34-36 degrees total- the results were predictable. Not only did the engine ping violently to the poor fuel, but two pistons cracked due to the detonation, the debris wedged between the piston and a cylinder wall and cracked the block. We were able to reuse the crank, rods, and heads from the damaged 389, but the piston choice cost him a new block and a rebuild- tragic considering this 389 only had less than 5000 miles on it. If my customer had listened to me the first time and ran forged pistons, he would have only had to build his 389 once.
I would also spend the extra money on upgrades like zero decking and dynamic balancing for the rotating assembly- the decking will help your engine against detonation and the balancing promotes longer bearing life. Your cam choice would depend on the heads used on your 455 build- clearily a different cam should be used if you're building a 9-9.4:1 vs. a 8-8.5:1 455. The cam you chose should run well in a 8:1 455.
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I don't think anyone makes cast replacement rods, so more than likely they reused the factory cast rods, which are at least 30 years old.
I remember googling "KB hypereutectic pistons", you will find the same story 72blackbird just told, it seems to be an unreliable piston for a lot of different engine families.
Once you factor in all your upgrades for this motor, you may be surprised to find it's close to the same price as what was quoted to you by the other Pontiac engine builders. Plus a Pontiac engine builder is going to include other top end stuff and the little details that are special to Pontiac.
My engine builder used KB ICON Forged pistons for my 400, the compression height is 1.72" so they did not zero deck my block. They had only 2 valve reliefs as well, which also helped with the total compression. I just measured my 6x-4 heads with a cc measuring kit and found they are at 93cc, so with my combination I'm at 8.7:1 compression. I will be running high octane even with forged pistons.
Also, you said you are getting a new rear seal, which is good, but I would just make sure it's either a Viton 2 piece or a BestGasket brand rope seal. If it's a factory replacement rope seal, just be aware you will most likely have to replace it.
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Geno and Angelo thanks (again and again) for all your thoughts. I took the info you provided and called back and after a 15 minute conversation the person I was speaking with suggested the following. Knowing I want street ability with power output in the neighborhood of 350/450 he recommended a stroker 400. It would have forged crank, forged pistons and H-beam rods. They would still do the replacing of the harmonic balancer and flex blade. For the rear seal it would be a Viton. They are going to send me an email with a full break down of the other parts. The options they told me to think about in the meantime would be porting and polishing for the heads and consider the cam for the configuration. A 400 is what my car had originally so I am not worried about the trainee. Obviously a 455 and a stroker 400 are different animals and while I'm excited about the forged parts going in I'm going to wait to hear what you guys think about going with this stroker before pulling any triggers. AND if you have input of the cam I had chosen and if I should spring for the port/polishing I'd greatly appreciate it.
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A stroker is beyond my knowledge. I know they are awesome though!
The back of the Pontiac How to Rebuild V8 book by Rocky has about a dozen different engine combinations by various known engine builders. If you have that book, take a peak at the combinations, I think a 400 stroker may be in there.
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Actually I do have that book and didn't think of even checking in it for info on a stroker. Man do I feel silly. You guys have spoiled me with a wealth of info, I will check it out this evening. This is the info I have so far from my contact at the shop on the stroker setup.
The stroker kit will make the engine a 461 stroker and it is a scat 4340 forged steel crank. The rods are actually a big block chevy rod 6.800, H-beam. And pistons are a forged dish piston. Depending on the heads I am going to try to keep you at about 10.5 to 1 compression. Will have the heads info shortly. I still need to choose a camshaft to use in the engine also.
So cam specs aren’t quite available yet as I am still waiting for a cost and I will go from there. We have lots of options cam wise but I need to know if you are going to run a stall converter or if you’re going to stick with stock converter. Also are you interested in going retro roller or stay flat tappet? I think we should also run roller rockers too, which we would have to add studs and guide plates to the build, but I think doing this is definitely worth it.
All of a sudden my options seem to have exploded and I figured best to get input from you guys. Also 10.5:1??? That is quite the jump from what I was initially anticipating. My excitement for a stroker was initially for torque and power in the low rpms but would this set me back in street ability? Pump gas still good?
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The 400/461 stroker is a well known combo, but the original Pontiac stroker combination comes from the venerable 455. It's possible to use standard 455 pistons, stock length 6.625" rods, and a stroker crank with a 4.21" stroke and 3.00" main journals to create a 400/455 stroker- this combo can be less expensive than a 400/461 stroker kit if the parts are purchased separately. The main advantage of buying a 461 stroker kit is the convenience- as long as the kit is balanced it's basically a ready to install package, making it as simple to build as a regular rebuild. Pontiac 400's can also be stroked to up to 440 cid with a 4" stroke crank, and even a massive 495 cid with a 4.5" stroke crank. There is also a 4.375" stroke crank available, but I have yet to see any builds done with this crank.
As far as the 10.5:1 SCR goes, it all depends on what size chamber you use on the heads you plan to run. It's possible to run up to a 9.5:1 SCR with Pontiac cast iron heads and 91 octane, but any higher compression will require 92-93 or race gas. Aluminum heads have twice the heat dissipation rate as cast iron, so it's possible to run a 10-11:1 SCR on pump gas with them (SD Performance does recommend a 10.25:1 SCR limit with 91 octane however). Head choice will determine how much power you want to make- 500 hp is the usual limit with ported iron head/roller cam combos, stock aluminum heads will make around 525-560 hp, and ported aluminum head/roller cam combos can make around 600 hp.
The 400 block you have may or may not handle a stroker kit, since not all 400 blocks are created equal- the later 75-78 no.500557 400 block is too thin in the main saddle area to handle power adders like a stroker crank, nitrous oxide, or a blower. Earlier 67-75 no. 979xxxx and 481988 400 blocks are thicker in this critical area, and can handle power adders like a stroker crank. Look for the block ID number at the rear of the block on the passenger side, above the oil filter bracket.
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When I speak with the shop today I will ask about the casting number off the core. The 400 is not the motor in my car but rather a core they have at their shop. They have a 455 core and a 400 with a 461 stroker kit they recommended. My initial interest was in finding a '70-'71 455. Their output for those years were supposedly 350/450 out of the factory which was my power goal. I told the guys there I'm using the car for street only and wanted to keep the power output ideally 350/450 MAX 400/500. I'm more interested in torque and obviously being able to fed the car pump gas. He suggested going stroker for getting the higher grade of quality components and gaining additional power. I'll get the cast number to confirm the year and see what options they comeback with for the heads/chambers and report back. Knowing my goals at this point and the two options of the stroker 400/461 or a 455 is there any particular consensus or is the jury out depending on the rest of the stroker build?
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Geno IS the MAN! You can also get ahold of Rocky thru this site if you have any questions about the info in his book?! He is a Hell Of a guy and very helpful and knowledgeable! He is busy tho so be patient! ;D
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Getting 400 hp/500+ ft-lbs. from a 455 or 461 stroker on pump gas is not hard at all for any Pontiac builder who knows what he is doing. Either combo is capable of producing monster torque with iron heads. The main advantage of the 461 stroker over the 455 is internal friction- the 400 has 3.00" mains vs. 3.25" mains for the 455, and has a slower bearing speed, which translates into less friction and heat generated. The 400/461 block also is a little stronger than a 455, since it has more metal in the main saddle area than the 455. So if the 461 is so much better than the 455, why is demand for the 455 greater than it has ever been in the last 30 years?
The 455 still remains a very popular choice because it's the original Pontiac stroker engine- it was making well over 450+ hp/500+ ft-lbs long before aluminum heads and stroker kits existed. Adding good forged pistons, rods, balancing the assembly, good heads, and required machine work for a performance build will yield the same results as a good 461, minus the cost of a stroker crank. The factory nodular iron crank is also good for 600 hp, despite what so-called Pontiac experts claim about newer cast 4.25" stroker cranks being stronger. You can use the factory 455 crank along with good quality forged pistons and rods, upgrade the 2-bolt mains to ARP studs, and it will handle 600 hp. I would only upgrade to a forged crank in the 455 if was using the engine in a road race or high rpm application.
There is also no definite proof the 461 makes more power or revs harder than a 455, although more 455's are getting rebuilt with 4.25" stroke cranks and 6.8" BBC rods (the main advantage being the larger bore of the 455 and a better rod-to-stroke ratio). So if given a choice between a 455 and 461 stroker, what is the best option? If you have a choice and both cores include the factory cranks, go with the 455- you'll save on the cost of a stroker crank and the 455 is already a proven performer.
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No, Randy- You da man! ;D
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I have the later 400 casting. Mainly because at the time I didn't know of the weaker block and I already had money invested. But, I think my build will be more than ok with the addition of 4-bolt splayed billet steel main caps and ARP studs. And other top notch forged rotating assembly. For info, I used the Ohio Crank 4.21" forged crank with 3" mains. Really nice piece.
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Geno I think that was the exact bit of info I was waiting to hear about the 455. I'm going to see if they can give me options for it based on what you said here. In the meantime can I get everyone's take on what they have quoted for me in regards to the 461? In particular which of the items listed as extras would be needed and which I can do without?
PON-461SLB
Item Cost Notes
Base price on 400/461 stroker engine $3,445.00 L/B comes with Gaskts, oil pump, and break in oil. Price includes balance and parts
Stroker kit consists of forged pistons, H-beam rods and forged steel crankshaft, made by Scat.
Core charge $400.00 Refundable minus return freight
shipping $195.00 Freight costs to a business in NY
subtotal $4,040.00
Extras
Port and Polishing $350.00
balancing Included
New SFI Balancer Included
New SFI Flexplate Included
Cam upgrade $411.00 New comp cam kit, With springs, retainers valve locks. Specs avaible upon request
Performance timing $84.00 New double roller timing set
Roller rockers $215.00 Full aluminum bodied
rocker studs and guide plates $110.00 Comp hardened studs and guide plates
pushrods $75.00 comp hardened push rods.
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$5285 for a 461 stroker with forged pistons, rods and crank seems reasonable, considering the rotating assembly often costs $1650-2100 balanced (depends on the brand of pistons and rods used too- be sure to ask what you are getting). $600 of that final cost is core charge and shipping,so $4500-4600 for a 461 long block is a typical price. I would also like to know what was exactly machined- a quality build should have been bored/honed with a torque plate, zero decked, main saddle align honed, stainless valves, heads serviced with a multi-angle valve job, hardened exhaust seats, bronze guides installed, guides machined for PC seals, intake surfaces milled to match the amount of material milled off of the block side of the heads.
I would also be concerned about what number iron heads were used- there are numerous Pontiac heads that have a 96-102cc combustion chamber. This size chamber will yield a 9-9.5:1 SCR on a 461, allowing use of 91-93 octane. The builder should also tell you what size pistons were used and how much the block was overbored- I don't think you'd want to buy a 400 block that was bored .060, which does yield 468 cid, but doesn't let you reuse or rehone the block should it need servicing. It's becoming harder and harder these days to find a standard bore 400 core, so I would be surprised if your builder started with a .030 over block- be sure to ask before putting the deposit on any build.
The "extras" listed are for the most part essential in a high performance build- you don't want a new cam installed with old valve springs, or stock used rocker arms. Full roller rockers aren't absolutely required, but do reduce heat and friction generated- at the very least you should run roller tip rocker arms (not as noisy as full roller rockers but better than stock rockers). The builder can also get a stroker kit with a cast 4.25" stroker crank that will save you around $300 as well- since you are shooting for 400-450 hp/ 500+ ft-lbs a forged crank is overkill and not required. No mention of 4-bolt main caps were made- not a must, since Pontiac 2-bolt main bolts can handle 500+ hp, but you should ask your builder about installing ARP main studs before machining the block.