Header explanation? Please

duster340 said

also to make full use of a real tuned header you want an equaly tuned intake side of your engine.
the thought behind a stepped header would probably be to be able to use the velocity of a smaller primarytube when still havig the greater flow of a bigger tube and the steps could probably stop reversion also but i feel most comercialy available headers use the smaller part of the stepheaders for easier acces to headerbolts in aplications where the boltspacing is to tight to uese a bigger tube.
not an expert just thinking alitle free

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RIGHT! Your comment goes back to the "match it all up" theory. If the individual parts of the package aren't matched, you can forget getting the absolute most out of a combination.

...and on the stepped header thing.....IMO, the stepped headers are good for two instances. In tight engine compartments (B/RB in an A body) or with mild to moderate combinations. The smaller first primary setion allows for some velocity increase going into the larger primary section.... kinda like a venturi effect with a carburetor. The stepped headers usually aren't much of an advantage for really powerful combinations.....say 500HP and up. But in the A body, we don't have much of a choice. That's why the TTI and Schumacher have HP limits clearly marked on their web sites.