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What are the gains and losses of either one? Do manifolds help torque more than headers or are headers just better overall? If an engine is rebuilt to original, do people look down on putting headers on and think it's better to have the original HP manifolds?

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I was looking at the summit headers but at the same time I've got the #'s engine. I'm just wondering why if headers do so well on ANY engine no matter what american company, then why did they waste the extra material on manifolds and just build headers which increases power by 30-50hp based on camquest?

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I was looking at the summit headers but at the same time I've got the #'s engine. I'm just wondering why if headers do so well on ANY engine no matter what american company, then why did they waste the extra material on manifolds and just build headers which increases power by 30-50hp based on camquest?

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because casting iron was cheaper then bending steel tubes and welding them. If you look at newer cars you will see most have header type manifolds than old fashion cast iron exhaust manifolds....

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a single piece casting out of grey iron in a sand mold with a couple machining operations is much cheaper to produce on a mass production scale than a fabricated header assembly. there's also a durability issue. how many 30-50 year old headers that were run year round in snow, rain, etc do you see that are still around compared to manifolds?

most of dulcich's "stock to mod" dyno flogs show ~20hp/tq increase with headers even on a stock big block....that's usually his first step in all of these, so it's hard to say what the difference is between say, a comp XE275HL cam (much larger than stock as far as area under the flow curve) with manifolds vs. headers