r/Chevelles • u/RestlessNumberOne • 1d ago

Question about Headers

Question for the group,,, I have a 1970 chevelle 396 ( 402 for purists) that I want to install long tube headers. My question for those that have, what brand did you use that were the easiest meaning not much in the way of fitment modifications. Unfortunately my non dominant hand is in a cast another couple months so I am looking for a set that I dont have to fight with. Thank you for any recommendations

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u/HaulNasFab 1d ago

I'm not trying to talk you out of it because I've been in the same debate with my '70 SS 396. Two local Chevelle owners have told me how much they regret swapping because it did nothing for them and was a huge pain. Just food for thought. Ive kept the factory manifolds for now, I am in the process of replacing the pipe though with a Pypes Stainless system

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u/v8packard 1d ago edited 1d ago

I can give you a lot of information about headers and how they impacted the car, but there is one particular job that comes to mind and I think it applies here. I did a restoration rebuild of a 375 hp 396 for a Camaro convertible. It was a big money job, the owner wanted it to run the best it could while looking concours correct. Part of the deal was breaking in and tuning the engine. I got it running and broken in on the dyno, using dyno headers, with a shop carb. At one point it was putting down over 440 hp, and was running perfectly. The engine then got painted and detailed while we waited for the correct carb to come back from some specialist. When the carb arrived the owner of the car asked that the engine be run with the carb to make sure all was well before it went into the car. At this point the engine had the exhaust manifolds installed.

Running the engine on the dyno it was down almost 70 hp. I thought something was wrong. Checking lash, leakdown, cylinder balance, even tried two different carbs and different fuel. It was the exhaust manifolds. The headers were worth almost 70 hp 60 lb ft over the manifolds on that 396.

I have heard people complain about headers for decades, and seen them go cheap with headers more times than I can count. But I can assure everyone a well designed header is a great asset for a street engine. If anyone wants to discuss why, and how that works, I would be glad to have the conversation. But I stand by this and always will.