[macdroid]

I have a numbers matching '74 Trans Am(400-auto) and I currently have Hooker headers installed. I am looking for advice on whether to keep the headers or go back to exhaust manifolds. If manifolds are a better overall choice, what are the absolute BEST ones on the market? What kind of performance loss is there? What are the advantages and disadvantages between headers and manifolds, other than the difference in horsepower output? All advice will be greatly appreciated.

[macdroid]

I have a numbers matching '74 Trans Am(400-auto) and I currently have Hooker headers installed. I am looking for advice on whether to keep the headers or go back to exhaust manifolds. If manifolds are a better overall choice, what are the absolute BEST ones on the market? What kind of performance loss is there? What are the advantages and disadvantages between headers and manifolds, other than the difference in horsepower output? All advice will be greatly appreciated.

[Goldbird]

It really boils down to what do YOU want on the car. If you want to keep it original, go back to your original manifolds, but since you have headers already on the car, I'll assume that's not the case. Headers definitely flow better than stock manifolds, about the best stock manifolds for the 400 are the RamAir style manifolds (about $300-$350 a set). I've heard a lot of bad things about trying to get headers to seal good, which isn't really an issue with stock manifolds. There are some headers that do have a good reputation for sealing good though, check the other topics on the forum and you should be able to find some feedback from some of the other members on that. Bottom Line: If originality doesn't matter, stick with the Hooker's since they're already on the car, they'll flow better than manifolds as long as you can keep em' sealed to the head.

[critter]

I have a 74SD TA. I'm running the Hookers. They can be a bitch to seal. If you're having trouble, try cutting the flanges between the primary tubes and using the copper gaskets. That fixed mine.

[Randy Frazier]

If you have a good exhaust to go with the headers, such as 3 inch head pipes and some good performance mufflers such as Flowmasters, the headers will produce much more power. If you have a stock size exhaust and don't uncork the headers, there is little to be gained over the cast iron manifolds. The bottom line is...if you are serious about improving performance, the first improvements are almost always needed on the exhaust. If all you are going to do is cruise, the cast iron units will be trouble free.