The eightlug twopiece rims are rated for 35 psi, and were used with the bias plies on the HMMWV. The 12 bolts are rated for 50 psi. Backspacing is 7 inches. The 37 inch MT (Military Tread) OZ tire is a D, with pretty high rating (Ill look in the morning in the shed). The tire is harsh riding, and not always too round. We had a total flat, the tire is so heavy, it looked like we had runflats installed, turned out it was just beadlocks. That tire was 14 years old (yes I know too old, esp. here in the desert). It looked perfect on the sidewall, no cracks, but once flat, with the truck mashing it, it did show the age big time. (BTW the MT is now the MTR, Military Tread Revised). IF you use the twopiece wheel, a beadlock or runflat is the only save way (blowout on a freeway, tire hopefully stais put, till you can stop).
Carrying a Ford, should be ok. : lightly loaded HMMWV (one person, 300 lbs) they call for 26 psi, Full load (10300 lbs) 35 front, 40 rear. The uparmoreds still use that tire, and a new rim, to carry the extra weight/pressures.
Mounting the tires is a workout (have done a whole set, by hand). Torquespecs and sequence are very important, new O Rings and possibly hardware is needed.
We got some extras, PM for info. BTW if a surplus tire is really nice, (new and lots of tread),unfortunately it usually comes with a nail....
