Snowman51
Assuming you are working on a 3100 series, AD truck (short bed) and, assuming that in my 1957 3100 w/SM420 has a comparable length driveshaft, I offer the following:
my (org) driveshaft is in the neighborhood of 60"+ long. Single shaft with slip just rear of the transmission. Served me well for ~200,000 mi in 60's, 70's and 80's. I will be reinstalling it when current and long going resto is complete. Trans, shaft and rear end are as from factory.
delky dave in wyo


1957, 3100, v8
2016 gmc 4wd