pontiac 400 in a g-body

[shotgun]

Here are the options in performance order:

1) stock logs

2) shortie headers need to be modded

3) 3 tube headers may need slight mods

4) Ram Air manifolds Bolt in

5)66/67* Abody Hedman headers mild "massaging/grinding"
68/72* Abody 1 pass tube will need to be "moved"

6) Cu$tom Header$

* larger tubes means more massaging

Depending on how much HP and displacement each step will add about 10 HP.

On logs,shorties and Ram Air the downpipe is critical , must be mandrel bent. Non-mandrel can cost 15hp.

Shorties are a push when compared to logs on mild(350hp) , smaller (400cu and under) motors.


You are correct , poly mounts don't exist.

I can make them using SBC poly inserts with your cores.

 

[robert87ss]

with the poly mounts you can just cut off the metal that sticks out of the rubber. is this how you do it? i bought a set of polys and they fit the '74 firebird engine brackets, but they are taller. so i went with the '81 301 brackets but the mounts would not fit the backets without cutting off the locating tabs. what did you run shotgun?

 

[shotgun]

I remove only 2 out of 4 tabs, trim them to match the height of stock mounts, bolt them together and then weld them up.

Use 301 engine mounts and never an issue.

 

[79GP6.6L]

thank to 79GP6.6L. i took his advice and modified the drivers side of a set headman 28164 shortys. i cut the flange off and got a piece of 3" exhaust from autozone, cut it at an angle to keep it away from the frame. then i welded the flange back on. it doesnt look to bad i think, especially because this is the first time i have fabricated anything.

Nice job! That looks good to me!

Take shotgun's advice on the downpipes. I made mine out of 3" mandrel bent U tubing from Summit. After that I reduced the pipes to 2.5" cuz I didn't think I was at the power level that requires a full 3" system.

I currently run the modified Pontiac 400 pictured on the previous page in my Grand Prix, and a fuel injected modified SBC with edelbrock heads in a 6 speed F-body. I'll take a Pontiac engine over a Chevy engine any day of the week. If you run a small block you can enjoy the advantages of less expensive fuel injection setups and cylinder heads, and other parts in general. I normally curse and throw tools when I have to change plugs on my chevy engine. I enjoy easy plug access on my Pontiac, and I think it runs stronger and makes more torque. There is a reason why, in 2010 you can build a Pontiac engine entirely out of aftermarket parts, even though GM killed Pontiac V8's over 3 decades ago. Please feel free to send me any unwanted Pontiac engines that have been replaced with Chevy engines. I assure you that they will be put to good use.

 

[robert87ss]

the car is going to the exhaust shop, no more custom work for me, the guy i deal with is the best around. oh yeah i am keeping the poncho, i just spent $1800 on a set of kauffman heads for it. im gonna have to put a 9" out back so it wont break.

 

[JBreu]

Say all you want about the sbc motor or the pontiac-------they are both great..BUt I bet I can get more HP and Torque out of my sbc cheaper then you can your pontiac............That being said........as long as either can beat the sh*t out of a FORD......No worries

 

[dan2286]

BUt I bet I can get more HP and Torque out of my sbc cheaper then you can your pontiac

That's the usual excuse

 

[JBreu]

BUt I bet I can get more HP and Torque out of my sbc cheaper then you can your pontiac

That's the usual excuse

BLAH BLAH BLAH

 

[robert87ss]

your right dan. but what the chevy crowd wont tell you is how many times their motor has be rebuilt, each time with better parts. or how much oil it leaks and burns. you would be better off just to build a buick olds or pontiac the first time and not have to worry bout rebuilding your chevy everytime you get beat by a ford. you wind up still spending the same amout of money.

BUt I bet I can get more HP and Torque out of my sbc cheaper then you can your pontiac

That's the usual excuse

BLAH BLAH BLAH

 

[adam6640]

To Shotgun
I am purchasing a 1980 grand am 301,I want to put headers on it, you said the 66 - 67 Lemans Tempest GTO headers will work,with a little grinding ? can you get headers for a 66-67 326 lemans tempest ,do you think they might work
thank you for your help Mike