Buckshot, my research agrees with yours on the 3100 trucks. No help for me though since mine's a 3600 (3/4 ton). Even thought many vendor fitment charts show the 3100 (half ton) kingpins (that do not require reaming) working on 3600 trucks, I suspect they are wrong. At least on my truck that's the case.
Kingpins showed up yesterday and no way they'll go into the bushings without the bushings being honed or reamed. Looks like it's going to take a 2 or 3 thousandth cut to get a finger press fit of .001".
I'll break it all down this weekend and install the new bushings, then to the machine shop Monday and reassembly next week (I optimistically hope).
RonR
