Independent rear end and pinion angle
 

I am installing a C4 IRS rear end in my 57 Chevy truck. I have studied a lot of pictures of other installs on the net. It looks like everyone makes the bat-wing carrier brackets square to the frame. I have also been told by one builder to make the pinion and engine parallel to the frame.

I finally stabbed in the engine and transmission to confirm the driveline and u-joint angles. If I make them both parallel to the frame, the working angles of the u-joints will be almost 6 degrees. (out of spec). Due the the rear end housing and transmission not close to the same plane, I have to tilt the rear end up 2 degrees and the engine down 2 degrees to get the working angles of the u-joints within spec.

Then I got to thinking. By tilting the rear end carrier, it changes the angle of travel of the rear wheels, or may cause binding on the lower camber bars. Am I going to induce problems by tilting the carrier 2 degrees? Maybe I'm over-thinking this again.