Lee,long tube headers may increase the lower speed power over stock, but a shorter tube or tri Y will out power either system from my experience. For racing ,a longer tube works for torque, however on a street engine that's not necessarily true.The addition of a exhaust system with a muffler and tail pipe changes everthing.On my modified 261, I use short untuned cast iron Fentons, a 2 into one system, and it outperforms a long tune header system, no problem.For most of our inlines, high speed is only 4500 rpm, most street driving is below 3000 rpm, the long tuned headers have no advantage in this situation from what I see.
