dgreif,
i've got a 50 3/4 ton as well. not unlike yours, the only thing left is the top "runner" for the under bed spare. i'm leaving mine side mounted (it's the only way it's been for as long as i can remember) but it's my understanding that the lower hardware is similar to the 1/2 ton set-up, just a little larger to accommodate the bigger tires on the 3600's. i could be wrong (it's been known to happen) but if i am, i'm sure someone else will chime in an correct me. do you have 16" 's or 17" tires?
where in mesa are you located? i'm in tempe so we can't be too far apart...
