I was advised by Robert, at AD-engineering, to use the 82-91. I used the 83 regular cab longbed which has the correct wheelbase but after seeing the frame I understood what he told me about a frame joint where the weld can be split, the frame shortened, and put right back in the same spot to be just like the factory did it. It's hard to describe but it's where the rear "C" channel frame mates to the front box frame. This opens the selection to include the stretch cab S10's also. If I remember right, they are 7" longer in wheelbase.
