Header primary sizes comparo
 

I talked to a guy that works with me that races dirt track about headers. He has a very high compression 350 and 400 engine that he runs in his 2 cars. These engines have cams in the 260+* @.050 range.

We talked about header sizes and power range. Keep in mind that his car never sees low rpm since he races 1/4 mile circle track and runs a 6.14 gear. His rpm's stay over 5000 and he turns his 350 to 8 grand.

He used to run 1-3/4 headers and now runs a 1-5/8 stepped to 1-3/4 header and says his car makes more power. He said that with his 1-3/4 headers the competition was pulling him off the corners. He says he also has used 1-5/8 throughout the header and made excellent power. Bottom line is that even with his engine operating at high rpm's where bottom end is not an issue, he still will not run a full 1-3/4 header due to lack of power.

So, has anyone actually been able to prove that these long tube 1-3/4 headers make more power across the board than a 1-5/8 stepped to an 1-3/4?

I used to run 1-5/8 on my 84 Z28 and 1-5/8 aint exactly small tubes.

It's real hard to use a dirt track motor as a test bed for what works on your street car. Like it's been said before, only one way to find out.. try it ;)