Rear Driveshaft angle and u joint questions

[offroadcowboy]

can anyone here can tell me how to measure correctly to figure out if my ujoints are within the proper operating angle. and also how to translate this to when i move my spring perches so that it stays the same .Thanks in advance.

 

[m j]

measure angle of machined surface of the rear dif (maybe the cover rails)
measure angle of machined surface on the drive line (this one is wide open, you could even use the front of the engine block as it should be square)
the pinion should be a bit low to account for spring wrap under power
how much is a total guess