[montoya22]

its not stupid at all, infact its good one. the truck I did it on was a 69 3/4ton.(what I found out was that the hole on the upper control arm was a perfect fit for the 73 ball joints. however the lower control arm hole was too big for the 73 ball joint. so what your going to have to do is

1. so to your local parts store
2. ask to look at 65 3/4 ton ball joints upper and lowers
3. ask to also look at the 73 1/2 ton ball joints, uppers and lowers.
4. compare the diameter sizes of the 65 3/4ton and the 73 1/2ton ball joint cases. (not the ball joint cone, but the casing that fits into the control arms)
5. what you should notice is the 2 years share the upper ball joint casing size.
6. the 65 3/4ton lower ball jointing casing should be larger than the 73 1/2 ton.
7. if the 65 3/4 ton lower ball joint casing is larger, ask to see 65 1/2ton lower ball joints, if the 65 1/2ton casing is the same size as the 73 1/2ton then you could just go to the junk yard and pick up a set of 60-66 1/2 lower control arms. if not then 67-78 lower control arms well.