1967-1972 Driveshaft Identification GM Rear

How to ID a Spicer Type 1310 Series Driveshaft U-Joint or What is my u-joint size? Spicer 1310 series u-joints with External Lock-Up (Snap Rings) has been used in production vehicles since 1940. The popularity of this u-joint for 4x4 and light truck...