Ok i just changed my whole rear end to a fourth gen with 3.42 gears. I had previously had a stock 10bolt with a 3.73 gears in the back. However, every since i changed that rearend the exhaust note changed. it used to be loud and ballsy. however, now it is only that loud if i rev it. would the new rear end even have anything to do with this change? oh by the way i am running stock exhaust on a 91 formy.

 

the swap from 3.73s to 3.42s will result in a lower rpm at all speeds, as well as a slower-revving vehicle when you step on it, and a higher load on the engine at all rpms.