Pontiac 400 Budget Build Help

[Daywee3d]

Hello everybody. I am new to the forum this is my first post actually. So I have only been working on cars for a couple years now, but I love building things and being crafty and I've always loved muscle cars. About a month ago I traded my 1996 Trans am for a 1980. It is a restoration project for sure, but it runs and drives and has a Pontiac 350 in it. Anyway, I want to swap a Pontiac 400 in it someday and want to know a good budget build to get around 400lb/ft of torque. Now heres the thing. I have never even swapped an engine, let alone build one but I am up for the challenge and the learning opportunity. I want this car to be a car that I do everything without a shop. I do not want to take it in to a shop at all and I want it to be 100% my work. If y'all would suggest that I start on other Pontiac engines instead of go straight to a 400, please give input but I just want a way to learn and grow in my engine knowledge and all around car knowledge. Again, maybe you would suggest starting with smaller engines like a fiero or something so I learn how Pontiac does things, but someone please give me advice. I am only 20 and and I will be getting married in the next year or less so the car is on the back burner for now but I am trying to plan out everything I want to do to it down to the last detail so I can get straight to it when the time comes that I can restore it. So if anybody has a detailed build sheet on exactly every part I should use to get 400-450lb/ft of torque that would be great. This includes what parts I can save, and what parts I should buy new and their part #'s as well. I hope that this is a beginning of an exciting journey for me and Pontiacs. Thank you!

[astroracer]

Hello (insert name here),
Pontiacs are very easy to work with. from the lowly 326 to the mighty 455 the blocks are, essentially, all the same. Swapping a 400 or even a 455 into your T/A is as simple as pulling out the 350 (as long as it IS a Pontiac 350...) and dropping in the new motor. Nothing to change, everything will bolt up. Building a 400 with 400lb-ft of torque is a simple matter also. Pontiacs are known as "torque motors". They are not designed to spin much more then 6,000 RPM from the factory And most stock motors after '73 or so will hardly do 5,000.
The trick with the 400 block is to build a "stroker motor". Kits are available to bolt in a longer throw 455 crank which will give you an increase in torque right off the bat. If I were to build a new motor for my '73 Firebird I would pull the 400 out and stroke it to 455. Google "455 stroker kit" or talk to Jeff Kaufmann or Jim Butler about your build. They do Pontiacs so they will get you set up right.
Mark

[andrewb70]

Post a picture of your 80 Trans Am engine. Unless someone specifically installed a Pontiac 350 in it, I highly doubt that you have a Pontiac engine. Pontiac stopped making engines in 1979.

Andrew

[Daywee3d]

Thank you for the tips! Can you really turn a 400mto a 455 by stroking it? I know with Chevy you can stroke a 350 to a 383 so a 55 cubic inch increase with a 400 is awesome if that's true! And yes the previous owner specifically put a Pontiac 350 in it

[MonzaRacer]

Actually all Pontiacs except 265/301 are same sheet of paper design. All Pontiac engines I have worked on all had aram-cast rods and should NEVER be wound past 5500. EXCEPT 455 SD and I believe 421SD. First of all any good Pontiac 389, 400,428,455 can handle blelow 600 hp with block mods after that, aftermarlet blocks.
Now ALL will make ludicrous torque even with stock heads properly prepped.
Budget Pontiac, pretty much any open chamber headfrom mid 60s up( careful there are two different pushrod lengths for early heads over later heads. I have built a 550hp 730lb ft torque 400 with opened up big valve 400 2bbl heads. Yes Edelbrock heads will hold better compression. and on Pontiacs closed chamber heads run in the 10.5 to 1 range Open chamber 8.5, use a dished piston you get 7.7.
Build a iron head Pontiac at around 9 to 9.5 and it can run on pump gas easy, dont use short duration cams for torque with closed chamber heads.
ALWAYS use hyperutectic or forged pistons if your gonna run it hard or rpm it and at least run some Eagle or Scat rods. Stock rods are crap.
Just keep duration under 300 deg. I like 270s or 280s duration. Lift depends on valve springs.
Most decent Pontiacs can push 500+lb ft of torque with no issue.

[astroracer]

Thank you for the tips! Can you really turn a 400mto a 455 by stroking it?
No, not really, I was lying to you about that...
I know with Chevy you can stroke a 350 to a 383 so a 55 cubic inch increase with a 400 is awesome if that's true!
It's not true, so forget about it... Putting a 455 crank into a 400 block can never be done and no one has ever done it... it would be stupid to even suggest it...
And yes the previous owner specifically put a Pontiac 350 in it

Come on man! Did you Google the stuff I asked you to in my first post? If you had you wouldn't have to ask if it was possible...

[Shawn01754]

It's simple to stroke a Pontiac 400 to a 455 ; https://www.google.com/amp/www.hotro...?client=safari Butler Performance and ESP joined efforts in 2000 and gave Pontiac hobbyists an affordable option to a 455 engine. They introduced a cast crankshaft for 400 engines with a 4.25-inch stroke, which quickly enlarges displacement to roughly 461ci during a normal rebuild. Crankshafts with other dimensions followed shortly. That article was written in2008. The prices have dropped way down for these parts. I'm not sure if you can do it with a 350 block. I've seen 400 Pontiac blocks for $100 and that way you keep the car running until the transplant. Don't underestimate the ability of the Pontiac 400. It's a great foundation for a power plant. Many blocked were also tapped for 4 bolt mains making it simple to make the upgrade. (Still need caps and a line bore)

[Daywee3d]

Seems like everybody is saying to make it a stroker but if that's the case, wouldn't it be easier to just buy a 455 and go from there?

[Daywee3d]

Astroracer, sorry I was busy and should have taken the time to read it but I didn't but I just recently went to Butler's site and also watched videos of stroker kit builds. Thank you for your input

MonzaRacer, since I am fairly new to this, I had a question about compression. I know with turboed cars you can control the compression, but I am unfamiliar on how you would do this by building an engine. Like how do you build an engine with a desired compression? I thought you just built it and found out at the end what the compression was.

Also, you mentioned Eagle. I see that many of the stroker kits on Butler's website are Eagle and they're slightly cheaper than the other ones. Is Eagle a reliable brand? One more question about stroking: if I bought one of those kits, would I be able to use my same lifters, springs, cam, heads, etc?

[rohrt]

Since you want to keep it pontiac. You should ask your engine build questions here: http://forums.maxperformanceinc.com/forums


Best advice for you now is look for a pre 1975 400 block to work with. The block number will end with 998. Most 1975 and up blocks end with a 557 code. These blocks are weak. They were lighten up by taking meat out of the mains and unless your doing a stock rebuild they are not ideal for a performance build.

The rest of the build will depend on your budget.

There are lot of options for the Pontiac motors these days.

[nobreaks254]

imo for your goals there is no need to do the stroker unless you need to buy a crank for the 400. Find a good 400 core (pre 75) and do a basic rebuild with 9.5 cr and alittle head work and a decent cam. Should make you more than happy.

[Daywee3d]

Wouldn't a $1800-2200 stroker kit from Butler give me more horsepower/torque than a cam swap and head work for close to the same price? And nobreaks254, I'm glad you mentioned the 9.5 cr because I have a question regarding all of that. I know with turbos, you can control the compression, but not sure how you build a block to be a certain ratio as so many people say to do. I thought you just build it and you get whatever compression ratio it gives you. How do you control what ratio you want to build your engine to?

[nobreaks254]

you still need to buy a cam when you do the stroker kit. Plus I would still do head work to maximize the stroker. You could always do most of the head work yourself with a little patience and minimal investment. To get your desired CR you need to know your bore/stroke, cylinder head and piston valve relief cc, gasket thickness and piston to deck height. Zero deck the block and mill the heads to get your desired CR. Hope this makes sense.

[andrewb70]

Pontiac engines altered compression ratio with cylinder heads, more specifically, different heads have different combustion chamber volumes. All Pontiac pistons are flat tops, so the combination of bore, stroke, and combustion chamber volume determines static compression.

Also, forces induction does not alter static compression.

Andrew

[OLDFLM]

I think the main question the OP needs to answer is what is he REALLY going to use this car for?
If it's 99.99% street driven that's a completely different answer than if he's building a race car that will only see the street on occasion.
Then the next question is budget... and we can go from there.

[OLDFLM]

Also, buy Jim Hand's or Rocky Rotella's book: "How to Build Max Performance Pontiac V-8s"