primary tube length help?

[MidTexCuda]

About to mock up my header build. I know I want to run 36" primary length.
Question- do I measure from flange to end of primary pipe in the collector or just from flange to collector?

 

[bOb shingler]

flange to end of pipe.

 

[MidTexCuda]

Thank you Bob.
Spent 9 bucks on mock up suplies. Cant wait to see if it will work.

 

[AJ/FormS]

Actually, I think the measurement is from the back of the valve to the merge-point in the collector. The difference wouldnt amount to a hill of beans though. Esp for a street car. And the smaller the cam(hence RPM), the longer the pipe can be.

 

[UOP]

Primary Header Tube Length and Diameter Calculator

http://www.wallaceracing.com/header_length.php

And here are some videos that may help

http://www.stainlessheaders.com/headerfabrication