My '66 SS was used as a drag car. I have been fighting a vibration that appears about 60 mph and gets worse the faster you go. I have read the forums about pinion angle relating to vibration. I have been looking over the car and tried all the many remedies but I think I have found something relating to this problem. Was there any time during the 60's that guys would change the lower control arm front pivot point to get better traction? It seems that the mounts that attach to the frame where the front part of the rear lower control arm have been moved higher on the frame. I looked through the access hole in the side of the frame where that bolt passes through and it has been welded about an inch and a half higher than stock. Could this be my vibration? Any help would be appreciated. And if anyone is doing a body off could you send me any photos you have of that area to my e-mail. Thanks in advance.

I would think you have a driveshaft problem, not a pinion angle problem. Old u joints ,worn tailshaft bushing, d/s out of balance. Have you checked those?

Thanks for the reply Turbo. Replaced u-joints, replaced extension housing bushing. Have not had the balance checked though. Will check that next.