My thoughts are that an M818 can be bought for less than an M813, from which I'd yank the bed anyway.
The frame may already be the right length. I'd like to have room for a spare and davit behind the cab and will need to get out a tape measure to see how it'll work. Since I already have cargo trucks, I'd be willing to lose a little bed length to keep the spare out of the bed.
I have a pristine 1986 M105 on 11.00R20 XLs, with fiberglass racks, that I'd sacrifice for the bed and racks.
After riding in some really rough places, at Rausch Creek with RickyOday in his M818, air ride, HEMMETT or CUCV buckets on spring bases are mandatory. CUCV buckets are cheap enough and OLDCHEV4X4 got me some spring bases from Coleman's for $20 each. They sure make a difference, especially on rough ground.
Doghead and I have discussed using a second front axle for the rear axle. In my brain cell I have a fuzzy picture of digging up a used hydraulic contol valve from a Skytrak forklift to control 4 wheel steering through 2 way cylinders.
That would allow regular front axle only steering, 4 corner steering with wheels opposed to thighten the radius and 4 corner steering with the wheels in the same direction to allow crabbing diagonally, all at the flip of a switch.
A winch, a few snatch blocks, chains, clevises, shackles, straps, yadda, yadda, yadda are pretty mandatory.
A turbo would be a definite plus but is well down the priority list. Maybe a winter project a few years down the road?
I think the whole thing could be done without breaking the bank. It'd give the boys and me a reason to work together on something other than antique tractors.
I've got a lot of shop and storage space so if I get this thought through far enough, I'll buy an M818 ASAP and I'll start hunting down an axle, springs and the hydraulics. I'll keep the M818 intact until I'm ready to pull the trigger.
I hope Household 6 lets me sleep in the house after buying another truck without selling one first. I may have to borrow the Number 1 son's motor home until she cools off.
Anyone interested in an M35A2, whistler, winch, hardtop, cargo rack over the cab, sprung bucket seat, singled 11.00R20 XLs (with an XL spare) and hubs flipped? Maybe your wife will let you stay in the house, too.
Lance