I'm looking for some input on a rearend vibration. I've got a 69 Valiant w/ 904 tranny, 8 3/4 rear, spool and 3.91 gears. Car drives and launches great but once I'm into 3rd grear above 3,000 rpm I get a winding and vibration in the rear that progressively increases with speed. Talked with a few guys, some say pinion angle, some say the rear isn't set right, and others say the drive shaft is out of balance. Where should I start? Thanks!
