I agree, the best practice is to wait and set the pinion angle when the truck is as complete as you can get it.
When you get to that point here is all the info you need on driveline setup and angles.
http://www.stovebolt.com/techtips/driveline/setup/index.html

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-