Driveshaft is not a problem, whatever needs to be done with it.
Install the rear axle and measure to see what you need. If the original driveshaft is to long or short take it and your measurement to a driveshaft shop and have the work done, also have it balanced too.

Grigg

•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-