I removed my original axle and measure it with an angle finder. With the axle upside down I put a level on the spring perch and leveled it. I then put the angle finder on the pinion flange, it was -7* which would become positive if I flipped the axle back up right. My transmission measured at -2* so in theory +2* on the axle would have aligned drive line angle. I think I settled right at +4* for the perches and welded them. So far in the car I have no issues. It’s hard to explain it. Use your original measurement on the the original axle if you still have it. I’m sure others will chime in.
