I don't think it's gonna matter much. Block huggers are not much better than cast iron log manifolds anyway, so it ain't like you're gonna screw up a scientifically designed system. I'm not trying to be rude or a smart-***, that's just the way it is. If you want performance, with a system that provides a low-pressure area at the next port in the firing order, use equal-length, long-tube tuned headers with an X or H pipe right after the collectors, then proper pipe size through mufflers of your choice to the rear of the vehicle. 1 5/8 inch headers work well on 350 or less motors, 1 3/4 works better on 383 and bigger. If you just want to move gases from one point to another without regard to adding performance, use something besides real headers.