Putting in the 55-62 pumpkin does not solve the open driveline problem. Welding is still required. A possible bolt on deal is to find a 55 first series truck and use that housing with the 55 first springs. you will have a choice of several transmissions to fit the open drive.

On my 59 gmc, I just changed the rearend. The cost was more than I would care to post. Not being able to weld myself set the price through the roof.