[:@]I have a 1965 Mustang 289ci taken up to a 300 ci completly redone engine making 350-380hp it original had a c4 automatic transmission but i switched it out for a
(4 speed toploader with a borg warner clutch hurst comp shifter and i noticed that i was getting a grinding noise in 4th gear so i pulled the transmission replaced the front input shaft and 4th gear and the nose housing and the front bearing the rest of the gears are completly perfect the whole thing is 100% inline and after i put it back in the car im still hearing a grinding noise in 4th gear,,,,,I heard somewere that this is normal but i dont want to chance it when im going 100 or so down a dragstrip. Any clues on what it might be?