400 Pontiac Qustion

[BlueDragon]

Hello.. I am new to this forum and I have a few questions that may need to be answered throughout my project. I have been on here quite a bit and I notice that there is a lot of knowledgeable people on here... so I am hoping to get some help.

I am currently starting on a 67 firebird and had a question about the 400. It has the 6x heads on it and I am wanting to get the hp over 400. I know that Edelbrock makes a package: Edelbrock Performer RPM Power Package that will get it around 422 hp.

Would you guys recommend this set-up or is there a better set-up? I have heard good things about the 6x heads but this package from Edelbrock comes with aluminum heads. Should I swap them out or go with a differen package?

[PT Goat]

Depends on your budget and intentions for the car. There are several aluminum head options (Edelbrock, Kauffman, etc) which will let you run higher compression and make tons of power. If you're looking for 400 driveable horsepower, your 6X heads are an awesome starting point and will run on 87 octane if you need to.

For what it's worth, I chose to use 6Xs on my 421 and spend the $2000+ I could have spent on aluminum heads elsewhere. My 421 is just under 9.0:1, very streetable, and should run in the mid-12s.

[Tom Welch]

I concur with PT Goat on the 6x heads. If you install the 1.77" exhaust valves the 6x head is as good as any d-port cast iron Pontiac head out there. If you can find Jim Hand's book titled, How to Build Max Performance Pontiac V8s, you will get several decades of the best Pontiac engine building info that is available, period. Paul Spotts is listed as one of several recommended Pontiac vendors. I am building a 67 400 Firebird, too. I am planning to use a 428 that I found several years ago for the power plant. Keep in touch, we will have lots to discuss.

[BlueDragon]

Thanks guys... so far you have helped a lot.

[Ralph LoGrasso]

I can't answer your questions, but welcome to the site.

[moparcolt]

I am also working on a 67 firebird wirh a 400 and 6X heads, I would love to have the Edelbrock heads but $$$ is an issue. I've chosen to spend it in other places. Mine are bowl ported with the bigger exhaust valves and I am sure this will be good for over 400 HP with the right combination of parts. Mine is really a pro-street car (tubbed with a roll cage) but I am going to drive it a lot so call it what you want.

[bgm890]

There is nothing wrong with using your 6X heads, just beaware that the most you will get compression wise is a tad over 8 to 1. When you build the short block, since you are looking at keeping those heads, you will want the block to be zero decked. You will also want to look into getting either Victor head gaskets or the moer expensive Cometic head gaskets avalible in your thickness choice from .027" and up. If you zero deck the block, I recommend their .034" so your quench is right on. You can mill your heads as much as .060", but that would be the last time you'd get them milled. Go .030", and do remember the intake side has to be milled appox. .020" so there is no issues bolting on an intake.
A good cam (and this really depends on head mods, and your goals with the engine) to make a true over 400hp with your heads ported, is a hyd. roller type cam. Exact profile can be dialed in depending on how far you go with the heads. A good reasonable head is the alum. KRE Dports or the about to be released Rollin racing CV-1. But it will easily make more than 450hp.

[speedster]

I am also working on a 67 firebird wirh a 400 and 6X heads, I would love to have the Edelbrock heads but $$$ is an issue. I've chosen to spend it in other places. Mine are bowl ported with the bigger exhaust valves and I am sure this will be good for over 400 HP with the right combination of parts. Mine is really a pro-street car (tubbed with a roll cage) but I am going to drive it a lot so call it what you want.


What color silver/gray is that? It looks really sharp on your ride.

[bgm890]

btw, going .030" on the intake side is best to match the .030" that comes off the bottom of the heads. But in a pinch and usually after a fight with the machine shop you can get away with .020"

[68Formula]

A good reasonable head is the alum. KRE Dports or the about to be released Rollin racing CV-1. But it will easily make more than 450hp.

I must have fallen asleep. What are Rollin racing CV-1 heads (who makes them and is there a website- or are they also by KRE). Thanks!