8 3/4 ?'s

Ok I talked to my brother today he fabricates Firetrucks for a living and I guess he has moved axels on trucks before. He said where they work they put all pinion angles at 4 degrees but he doesn't know where that number cam from thats just the way he was taught how to do it. We put our heads together and we are wondering if we measured the angle of the 7 1/4 before we took it out it to use it as a guidline or since the 8 3/4 pumkin is longer would it change the angle? Also I have a 71 duster with an 8 3/4 under it could we measure that to get an idea also? Also I forgot to bring this up with my brother but are we going to need a drive shaft to figure this out? I am going to need a shorter one and I can't really order it till I have the rear in place to measure for it. Also whats the best way to get the car up in the air to work on and yet have the car sitting like it should? Can we put jack stands under the rear end than under the lower control arms on the front?

Green67Cuda will those pieces you fabed up also work with caltracs?