has anybody modded out a some of the big bolts with newer big axles? disk brakes? big diesel motors? custom flat beds?
Sounds like my truck project, although I haven't gotten to the flat bed yet; it is one the list.
Start walking through junkyards looking for axles and parts, take a tape measure.
Here's a tech tip with some ideas for axle swaps
http://www.stovebolt.com/techtips/Welcome,
Grigg