I'll be following this thread.
I am doing an axle swap in my '50 3600. I went with a 10 bolt 8.5 ring gear rear end out of a ZR2 Chevy Blazer because it's 63 inches wide wms-to-wms.
I'm going to weld up my spring perches so they match the stock axle perch/pinion angle (haven't measured the trans or perch angles yet) and when the truck is ready to drive I'll re-measure when it's loaded and use shims to get it right. I plan on lowering the rear about 2.5 inches, so I already know I'll have to shim it a little to get it right...
If you want an easy explanation of driveshaft angles and WHY you need to get it right, check out this Youtube video:
Pinion angle explained
