I have the system on my 68 with built 350, sounds absolutely awesome. I get compliments all the time. I dont know how restrictive it is but i think its worth a little backpressure for the sound, it doesn't sound quite like the normal FM's, slightly quieter but just has this cool tone, ive never heard another exhaust even flowmaster stuff that sounds just like it. Im putting in a way built 408 small block right now that should probably have a 3" system but im going to use it anyway, really thats how good it is lol... just my opinion of it.. i actually have a bunch of video of it and me going down the 1/4 but i have no way to get it on my computer..
