[LT7A]

I have the FM 50 on my Trans Am and it sounds fantastic. I'm not given to overstating things or giving myself props, but if you want to hear your motor, it sounds great. I had a FM 70 on a TBI truck and it was toooo quiet. I swapped it out to an FM 50 and it was perfect. Then I went to a high flow cat and it is now a little too loud. Probably you want the 70s. The 50s sound good but are pretty aggressive. If I was doing it, I'd run 50s with adding the pipes out the back. And just to confuse the issue and possibly discredit my whole post -- both vehicles are 350s not big blocks. In addition, they both have stock manifolds. I thought I'd chime in because I have experience with the two series you asked about. Tell us what you choose and how you like it in the end!