What you have is the garden variety SM 318 3 speed column shift transmission. The K 8 60 = Nov 8th 1960. There was a 3 speed overdrive available, a Warner Heavy Duty 3 speed (rare), an SM420 4 speed, and I believe a Powerglide also. Basically the same 3 speed in trucks from 55 through about 63 with the long tail housing, from 64 to 67 (in some models) had same trans with a short tail housing.
Fred
