HELP!!!!Put in 8 3/4 rear and it vibrates real bad

But, in an earlier post he has one wheel that wobbles, he switched the wheels and still has the wobble. Either the new bearing he put in isn't seated properly OR something is bent or possibly both.

I don't know how much strain the driveshaft would have put on the rear after the car was set down with full weight on the rear. If it wasn't shortened it probably went in with the rear suspended and then bound up right good after the weight was put on it. I can only guess right now.

I asked if he had it shortened and haven't heard.

Sounds like he has more than one problem. I agree you need to post a picture of the yoke so we can see what yoke you have. Hell it could be a 1330 or 1350 also. And your right we can only guess without more information.