What's the correct pinion angle for a 9" Ford rearend?
My '53 Chevy 3600 had a 9" Ford offset rear end and a two piece driveshaft. It ran pretty smooth at that time.
While doing a frame-off restoration, I decided to convert to a single piece driveshaft and set the rearend angle more in line with the driveshaft. Converting to a single piece driveshaft and resetting the pinion angle to 3 degrees has resulted in a bad harmonic that starts about 35 mph and increases with speed.