You probably have a 3.90 ratio. A 3.38 was available, so a bolt-in will be "possible". Correction in next post from Fred.
Use the search function on here to read all kinds of info on this issue. Swapping dropouts would be nice and easy. If not found, then consider 1965 and above for non dropout/modern diff.
It's no surprise, they had torsion bar till 63. Coil rear up into the 70's. You don't need to identify Spicer from Dana. They are the same company and the axles are called corporate now. GM is the "corporation".
Complete diff swap:
You need to decide on what ratio you want 3.08-3.73 or what. Your basic task is the width. Find a differential width that is close and has the ratio you want from a donor Chevy or GMC (Dana 44). A 10 bolt or a 12 bolt. You may have to find someone who can do perches/trailing arm mod. Leaf springs were an option about 1971 or so. You may run into one of those and modify to fit. Of course you will need to find a 3/4T so that the lugs are same as front.
Last edited by bartamos; 07/28/2018 7:02 PM.
