/6 questions

Personally, I would go with surplus smaller sized 2 to 2-1/2 ton deuce and a half powertrain with multifuel continental or perkins diesel and a Clark or Rockwell 5 speed from an 80's f-600 to f-800 or the like. That international has so much extra framing and cradling for the engine under the front that it could easily stand it. I honestly believe you have the room for that. Grab the 6.78:1 axle from the deuce as well as it has a similar, if not the same, 6 x HUGE bolt pattern. My God Man, if your going to build at a truck (especially one of this magnitude), build a TRUCK, Lolol! (Sorry, we have a different mindset in this part of the country.) All joking aside, I found a 56 a while back that I thought about getting but it was too far gone. A relatively easy swap over is a mid 60's to mid 70's Ford FE and Borg Warner T- whatever it is four speed from a F-250 but preferably F-350 (Bigger clutch and some extra H.D. goodies) as it is one of the more common adaptations. The International has a B-W transmission and bellhousing that is dimensionally close, and if you get it from a wrecker you might even score some other things like Thompson steering set-up and hydraulic master/slave clutch actuation. In the end though, like everyone else says, this makes the 300-6 an even more attractive option. Plan on a newer Dana 70 or GM 14 bolt, save yourself some headaches with the split rings with eight lugs on the rear. Maybe even grab a solid front axle with eight lugs and brakes you can get parts for as well. If it’s more feasible to stay with 6-lug, there are some you can go with nato/military 6 lugs. Your only limits other than funding is your imagination, binder planet is where I found a lot of this out at myself.