Michael,
I have a '53 3/4 ton- originally 4.57:1 rear end. I put in a "pumpkin" from a '72 Chevy 3/4 ton van with 4.10:1 gearing. It took about half an hour with a good helper. Make sure your donor pumpkin is the higher gear ratio by counting the revs. Mine was marked but I turned it anyway before installing just to make sure. Find a junk yard that does 60's-70's Chevy trucks. I paid $250 for mine- well worth it. I can easily do 65 mph with my '54 235 and stock 4-speed. Good luck.
Tyler
