Author Topic: '78 T/A lots of good advice looking for some clarity for Torque and HP upgrades  (Read 7843 times)

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Offline raypfaff

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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

Offline oldskoolubr

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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!
« Last Edit: March 18, 2013, 11:07:16 PM by oldskoolubr »

Offline hada76

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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
'76 T/A 455 4sp   sold
'78 T/A Y88 auto  sold
'79 T/A WS6 4sp
'70 Z/28 4sp

jeff

Offline Chuckles

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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.

Offline 72blackbird

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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

Offline oldskoolubr

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^Yup Always set a Budget, Even tho you know you won't keep it!  ::)  Still a good starting point!

Offline raypfaff

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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.
« Last Edit: March 13, 2013, 12:44:06 PM by raypfaff »

Offline brian c

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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.

1978 Y88, '70 455 HO block bored 0.060, TH350, 3.42:1 gears...Oct '08 Fbodywarehouse Calendar - Woot!
1980 Firebird - no engine/tranny... to be pacecar clone

Offline raypfaff

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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?

Offline 72blackbird

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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


Offline Angelo

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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.
81' ex-Turbo Trans Am - Resto-mod

Offline raypfaff

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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.

Offline Angelo

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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.
81' ex-Turbo Trans Am - Resto-mod

Offline raypfaff

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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?
« Last Edit: May 12, 2013, 10:34:56 PM by raypfaff »

Offline Angelo

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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.
81' ex-Turbo Trans Am - Resto-mod