My local O'Reilly store loans out a thread restorer kit, a bunch of special files to match most threads. I used it to clean up the threads on my drive shaft carrier. Worked great, and while they "sell" it to you when you pick it up, they return your money (or cancel the charge card) when you return it. Might be the easiest way to solve your problem.
Tim
I am currently digging back in to a 1953 3800 (one ton) with a nine foot bed. I've owned it since 1979, and drove it until 1982 (or so). My wife got me involved in restoring it back in 2002, got the body removed and the frame redone, then things came up. Now I am retired and starting again. If anyone is interested I have photos on Imagur (
https://timwhiteblues.imgur.com/ ). I live way back in the woods in the Ozarks on 40 acres at the end of a 2 1/2 mile private road.
Tim