I ordered this system for my '70 vert that was originally a 351C-2V, FMX car. The H-pipe included with this kit was spot on - for an original transmission car. I forgot when ordering that I'd swapped my tranny for a modern T5 which resulted in interference with the crossover of the H pipe. I had to have it modified by an exhaust shop and that resulted in a need to adjust the clearance at the muffler hangers too (using OEM muffler hangers throughout). I'm sure the system manufacturer could have accommodated this from the start had I remembered.
Note - the mufflers supplied are very quiet. I asked for the next level up in sound but due to an ordering mix up, I didn't get those and once on the car it was too late. No big deal, just not as deep a sound as I was hoping. Overall though I'm very happy.