Actual Header Lengths

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Mar 22, 2005 | 12:10 AM

soundengineer

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From: Chicago IL

Actual Header Lengths

I'm trying to pick a header..and I want to pick one that is truely the right length for what my setup will be...

basically wondering who's Longtubes are what length primary's
example...
Brand A Primary length 34 inches on 1.75 tubes
Brand B Primary length 32.75 inches on 1.875 tubes

make sense?? can anybody help me??

Mar 22, 2005 | 11:04 AM

white2001s10

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From: Fairview Heights Illinois

Quote:

Originally Posted by soundengineer

I'm trying to pick a header..and I want to pick one that is truely the right length for what my setup will be...
basically wondering who's Longtubes are what length primary's
example...
Brand A Primary length 34 inches on 1.75 tubes
Brand B Primary length 32.75 inches on 1.875 tubes
make sense?? can anybody help me??

Brand A will build power sooner in the RPM range than brand B.
I would try to match the primary diameter to the size of the engine and the power range it will be designed to work best in.
I'd go with a length that compliments that same power range.

If you were looking for a high RPM power peak on a large cube engine like a 408 or bigger, then the 1.75" tube may not be a good match due to exhaust velocity rising too early in the RPM range. In that case you'd go to a larger size to match the cubes.

If your shift recovery RPM is very high along with your power peak, then it may be better to run the shorter length primary. There is software out there to match primary length to RPM range, but if you cannot find it, talk to a competant header manufacturer.

Since most people racing quarter mile with their street car run automatic transmissions with under 400 cubes, and peak power relatively early in the range, the best pick would be Brand A. It just depends on combination... and even then it's best to actually test to see which one works out the best performance wise, since dyno's aren't the end-all.

Mar 22, 2005 | 06:05 PM