8 3/4 pinion angle

: perch welding From: DoctorDiff
I assume this is for an A-body?

If everything is stock, you can weld them out of the car:
43" on center, perches level, pinion 5 degrees up.

If you changed a bunch of things, you should mock the housing into the car and set your pinion angle based on the transmission centerline. For most street/strip cars make the pinion centerline parallel to the transmission centerline, then roll the pinion downward 3 degrees.

this is right from dr. diff