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

Ok wheel looks like it warped when turning, but the wheel is not swapped wheels still does it. But It looks like it is the drive shaft. Son put driveshaft on and where the u joint goes on is 4 1/4 inch which is 1 inch bigger than my u joint in width. What kind of car would this center section come off of. I have another one that is the same as my 8 1/4 was.