I have a 92 gt with a t -trim, and a whole bunch of other mods, it is making 602 rwhp with an lentech aode. I still have a 2.5 exhaust. Would I see alot more power with a 3 inch exhaust??? and would i NEED TO GET IT RETUNED??
Joe Dasilva built the car and Anderson Ford tuned it with the PMS.
Considering most NA 347's pick up considerably with 3" exhaust I'd certainly think you'd stand to pick up a lot. That's a lot of power you have. As far as the tune, throw a wideband on and see. I think you'll pick up quite a bit.