Mar-ktech -That's an interesting call & may have been the answer (read on) -if something like "tapping" loading dock on a regular basis with the rear bumper had occurred….
However, I went back to the shop today and took some measurements. Again, a very straight looking frame was measured every which way & it came up within 1/32"…hmmm
…so, I went back to the beginning and measured the height of the blocks and there was the main problem. It seems (after calling around) that mounting blocks are sold in anywhere from 2" to 2-3/8" in height. Mine were higher rather than lower. After fudging around a bit with the mock-up, we figure that with cutting the blocks down to 2" to 2-1/8" & using just a 1/4" rubber pad at the rear sill we will probably have about 1/8" (or less) to shim.
I have to say that the new Mar-k bed sides and cross sills go a long way towards making a good, accurate fit possible.
