So I wanted to start a topic to discuss designing an custom exhaust system. I have a 3.7L in a 1966 Mustang. I just got done building a set of equal-length long tube headers for it....but wanted to start thinking about the rest of the exhaust system. From what I have read since v6s are inherently balanced(unlike v8s) they gain no actual performance benefit from a H-pipe or X-pipe(though it does alter sound). Presumably it is actually better to run true duals on a v6...with a separate system for each bank of cylinders since it avoids the turbulence of a crossover pipe of whatever type. I was wondering if anyone had more insight on this idea. It would certainly be simpler to have true duals(and slightly lighter). My goal here is to build a system that squeezes every last HP out of the exaust...the plan is true duals into a glasspack on either side with a resonator after each pack to hopefully tune out some of the resulting drone. The headers themselves are 35" primaries of 1 5/8" diameter reduced down to 2" at the merge collector before returning to 2.25" after the trumpet portion of the collector, and 2.25" piping all the way back.