How long is the shaft and how many RPM?
My Cuda has the motor moved way back and it has a Powerglide, the drive shaft is small diameter and short. The former owner had a Blown alcohol B1 motor in it with 5:57 gears and 16x33x15 inch slicks
Once I found out what ratio those gears actually where, I was told that it had either 5:13 or 5:38 in it, I swapped those gears out for a set of stock Dana Corp 4:56 gears
I think it crosses the finish line in the 1/4 mile now right at 7000 RPM.