i had 1 20 years ago in a 383 street car, then put that motor in my race car and really liked it.i took the 3.91 gear out one time and put in a 3.23 but at 35mph it felt like it had a miss, where the cam was trying to lope. so i put 4.30 in it. i shimmed my rocker gear up for near zero lash and run it hard.