Mocking up/setting up pinion angle

[ChadW]

I am trying to find a way to get my pinion angle set and perches welded on my rearend now, while its easy to get to everything...

I am on full air ride with custom crossmember and tubular A-arms, as well as a large step notch in the rear...the truck will lay frame...

My question is, is it possible for me to get my pinion angle set now, while the cab/bed is off? I am getting ready to install the power plant and trans..Ideally, i could get the driveshafts made (2 piece) and get the pinion angle set while i can get to everything...I have read that you need to weight of the cab/bed on it etc etc..but for the life of me, i cant figure out why that would matter on a truck on air ride...ride height is ride height, no matter how much weight on put on it...can someone help clarify this for me please...

additional question: Possible to use a 2 piece drive shaft from a square body and have the longer rear portion cut down to size?

[mongocanfly]

If you know the ride height of the frame you can set the frame there and set your pinion angle...
The reasoning for have the body and drivetrain in place is mainly gonna affect spring style suspension..where the more weight you add, the more it compresses....
Almost any drive shaft can be made to work...as long as the ends match what your connecting to....I'd talk to the driveshaft shop and get their opinion of what you need and if the parts you have will work..

[PGSigns]

Set the frame on blocks at ride height with rear tires you plan to run on the rear end. Set the engine and trans in the truck and check the angle of the engine. If you are using mounts designed for a stock height truck the engine angle will be down in the back more than the ideal angle. The 3 degrees that a lot of engines are set at is so they point to the rear suspension in about a straight line. With the rear end a foot or so higher than it started life the rear of the trans needs to come up. Get it to the point where it is pointing at the rear end and take a look at the working angles. The you can adjust it up or down and your pinion angle to get about a degree of working angle in the ujoints. Once you have a good relationship between the engine and the rear end you can set the mounts front and rear. Any good drive shaft shop can build you what you need for the two piece to fit your final setup.
Jimmy