I prowled the wrecking yards looking for a one piece shaft. The SM420 is a short transmission, so a one piece would be relatively long. Found some shafts on Dodges that would work, but the diameter of the shaft is too large. I found a long box GM truck with the 4 speed had the two piece shaft. Our 63 C10 had the two piece shaft. So I talked to the driveshaft guy and he recommended a two piece shaft; said I would be pushing it with a one piece.
