X & H pipe vs straight dual exhaust

My latest purchase is a 71 R/T charger with aftermarket exhaust. Friday I ordered a complete stock system from tom swope and had a discussion on what was correct for that car. Originally a 440-4bbl car with no tips and turn downs. The car has been switched to a six pack setup, which made my decision to upgrade the new exhaust to the six pack/Hemi style with the rear resonators and tips. Tom had indicated that the six pack cars did not have an H pipe installed per the blue prints. He indicated some may have made it out with an H-pipe, I ordered it without.