I want to have my truck 8 3/4 housing shortened and the perches flipped to the other side to swap into a '70 Duster.

1. Are the perches supposed to be perpendicular (90*) to the face of the housing where the pumpkin goes? Or, are they angled up or down a few degrees?

2. I know the perch hole centerlines should be 43" apart, does that mean 21.5" each side from the centerline of the big pumpkin hole, or are they offset one way or the other?

Stock A body perches set pinion 5* up

43" on center for perch spacing

Why not use a B Body rear?
They're not expensive compared to ordering new axles and cutting a housing down...

I'm piecing this together with parts I already have on hand from years of accumulating jun...errr, emergency spare parts.

I already have axles, center sections, brake stuff, etc.

And the truck housing, which I'm tired of shuffling around the garage. Might as well use it.