I have a 1965 Chevy on a 1973 4 x 4 frame and from the reasearch I have done I'm sure the rear end is the GM 14 bolt that seems to be the standard on K 20's from 1973 to 1981. The numbers on the front left side of the axle are 167 then below that 3877323. On the front left of the differential by the u joint are the numbers 3977354. Also stamped on the axle on the right side near the drum are the numbers RF7G1812. Can anyone tell me how to decode these numbers for more information. Thanks. Pictures of the truck are at http://users.sisna.com/brublack/truck/index.html
