I am new to working on motors and would like some advise. I have a 64' grand prix that has a 76' trans am 400 in it and it is pretty slow. which would be an easy way to gain some horses? I got some headers for it but haven't put them on yet. thanks for any advise.
Hmmm. I don't have any specific advice because I don't know anything about your motor but you might have better luck if you post some more info about yourself and your car. The HAMB has is kind of a "community"... which isn't nearly as gay as it sounds. My advice is to fill out your profile and post some info and pics of your car. Seems to me a 400 could haul some ass but have you checked your compression to see if your motor is whupped? If you're still getting compression then you need to find a cam that's matched to either Bellflower Boulevard Cruising or AWB Launches depending on your preference.
You might want to clean off the pad on the center section that has a single digit stamped in it that designates the gear ratio. If it's got 2.56 or 2.69 gears, a change to 3.08 or 3.23s will do more for acceleration than some engine mods, especially going to a hotter cam, which would probably make it slower off the line with no gear in the rear end.
I have a '68 400 in my '64 Catalina convertible. I put a mild cam in it, a 4 bbl carb and electronic ignition and that's about it. It's better than stock, but it's still a big car and not going to turn 15's without some more extensive mods. But, it's good enough for me. I did have headers in it once upon a time and HATED them!!! They did not produce any more noticeable power, but cooked starters at an alarming rate. I put heat shields on the starters, wrapped the headers, bought the high dollar small and torquey starters.....all to no avail. The headers just ran too close in that application and you could pretty much count on not driving it across town to the magazine stand and then get back in to start it up without letting it cool off for a few hours. Let's not even mention how many times I had to replace collector gaskets! I finally gave up and put the stock manifolds back on and have had no problems since. My advice: no headers!!!!!!
Compression or lack of... most of the 400s from that era were 7.6to 1 compression way too low to make any real power.
axeman39 is right. 70s 400s were really underpowered because of low compression. Try and get a set of 68-70 GTO heads. Some of the casting numbers to look for are 12, 13, 16, 48, 62. They have much smaller chambers and will significantly raise compression.
Regardless of the relativley low power of the late 70's Ponchos compared to the early motors, there is no reason that engine shouldn't move your 64 easily. Your 64 is actually the same weight, or more likely, lighter than a 76 Trans Am. I think you need a tune up, or your your motor is tired.
Well, how slow is slow? 14.00 in the quarter to slow? Then I can suggest some upgrades. There are many people with low compression 400s making good power. But if you mean what I think you mean, you are saying the car won't keep up with traffic. That 400 should smoke the tires all day long, even though it won't make the quick 16 cut. In this case, I think your timing is setup poorly, and/or your carb needs adjustment. Throttle open all the way? Have you checked the basics before you bolt on a torker intake?
Spend the money on a nice set of heads and/or pistons to raise the compression up to about 9 or 10 to 1. The difference will astound you. The list of things you might do along the way is limitless, not the least of which should be a mild cam and a sound rebuild. After that, you'll know much more about your motor and be one of those weird, feakishly happy to race, Pontiac People. Then you just need to stay up there in Jersey.....
Sorry, Axeman is wrong. http://forums.performanceyears.com/forums/showthread.php?t=452561&highlight=low+compression+400 Here is a link to a discussion on some late 70's 400's running 10s in Super stock. Sure, they have big roller cams and such, but the compression is still stock. I'll ask again, who tuned your car?
The book I have shows '76 400 conpression ratios around 7.6:1, if you post the code on the front right of your block I can probably come up with the exact stock figures. A cheap improvment might be even some #15 heads - they'll bump the compression ratio up a bunch but they're not expensive or that hard to find. But you have to play games to find heads that won't take the ratio much over 8.5:1 for pump gas. But I'd look at the rearend ratio first, and I'd define slow -
There is a very good book on building street style Pontiac motors by Jim Hand called "How to Build Max Performance Pontiac Engines". His focus is on making torque for street power. There is tons of useful info on parts selection to maximize torque. Get it. Rick
my engine is a 76 trans am engine, with a edelbrock performer 4 bbl carb, edelbrock performer intake manifold and thats is right now... how slow is slow? well about as fast as my moms 95 mustang that has the 3.8 in it which is pretty sad.
Yep, that's sad. You've got more in her. You need to learn how to tune it. A new advance curve will be your biggest bang for the buck. Get Jim's book before you spend any money or tear your motor apart. It has tips on squeezing the most out of a low compression Pontiac. http://www.themotorbookstore.com/pontiac-v8-performance.html That will save you a shitload of frustration. There are recipes in there for a powerful Pontiac street motor. Also, sign up and start reading the tips on the pure Pontiac boards, http://forums.performanceyears.com/forums/ http://classicalpontiac.com/ Do you know what gears you have out back? 2.93 or 3.08s are fine for now, but if you have a 2.41 or 2.56, you need to get more gear. Headers are a big plus for Pontiacs. I'd start there for the changes. But first, you need to tune it right. Search those forums for "Advance curve"
Also, get Pete McCarthy's book: http://www.amazon.com/gp/product/B0006ESYIU/102-9661772-5340107?v=glance&n=283155 That book changed my life
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