Hemi Joel is right. I worked with Schoenfeld when I made my headers and he regularly makes race-application only headers for small time groups like NASCAR & World of Outlaws. He has his own dyno and has proven that unequal length is often better. On one engine, he had runners that varied by more than a foot and it gave the best H.P. numbers on the dyno. He prescribes by the theory that rather than an engine being a set of cylinders working together, they are really a series of individual single cylinder engines working individually. Yes, you want them to work the same but equal length doesn't always equate to that. Bends are more critical. -EM