Thanks for the advice. The rear end is a brand new complete Moser 12-bolt/eaton posi. The drive shaft is new and balanced.
I got the new transmission mount in and it moved the transmission angle to 2* down (from 4* down). So, I am going to shim the rear at 2* up to compensate. Then I am going to verify that the pinion angle is less than 3*. If I still have vibration then I suppose I will need to have the transmission looked at and possibly rebuilt. I read that a tranmission bearing could also cause vibration and my Muncie M-21 2nd gear is a major whiner. The vibration has much worse in 4th than in 3rd (although still there) so I am figuring the bearings may be the problem if the angle changes don't resolve the problem.
Does anyone with a 1st Gen camaro have any specs on transmission angle and pinion angle relative to ground? I am wondering if my setup is abnormal somehow from stock.