Hey guys, I know all about the length difference between a 69 and a 64 Chevelle rear end so I don't have to ask about that. What I really need to know is will the pinion angle get screwed up if i put a 69 rear into a 64 Chevelle "Using the 64 Chevelle Upper Trailing arms"? OR do I also have to install some upper trailing arms from a 68-72 12 bolt rear? Thanks in advance for all your input. Regards, Pat

Pat you will need to use upper arms from a 65 - 67. The 64 bushings and the casting they mounted in were smaller than the 65 and up. The arms will rub on the casting and be real hard to line up for the bolt. The 68 - 72 arms are to short.

Philip, You just saved me a whole lot of time and aggrivation!!! Thanks very much. Pat

Pat the 64 upper arms have eccentric washers on them for adjusting the pinion angle. It is the only year the factory did this. Below is a pic of the differential end of 65 arm. Notice the bulge in the top to clear the larger casting on the rear end. If your arms look like this they will work.
http://www.chevelles.com/showroom/64elcamino/65upperarm.jpg