Oh yeah! Big time difference! Just going from 3:23s in my 383 4spd 68 Coronet to junkyard sure grip ( 50 bucks, in the 90s) 3:55s was a massive improvement! You could jam down the interstate in 4th, and slap 3rd, Man! YEEEHAWW! the 4:56 set I put in lasted about a week, it was a fun stoplight slayer, but trying to get anywhere on 275, 75, I 4, was not a working deal.