It would work. You would have some time and money into it but you could pull it off. Is the truck 4x4? Depending on the length of your 351, tranny and transfer case you might need a little stretch in the rear. I think you would have enough room to have decent driveline angles with out stretch depending on tranny choice?
The 351 is shorter than the 4.0 but its wider so you need to mount it forward or do a body lift or both. Electric cooling fans will buy you some room up front for placement too.
I would stick a C6 behind that 351. I had that set up in a FSB and it was a mean rig.Would of loved to transplant it into a jeep..
One thing I hear over and over again is, when you swap engines, you dont do anything because of existing components or cause its easy. Like where your tranny is or you want to re use your drivelines. None of that. You put the engine in where it is optimal and remount everything else and have drivelines made...
91 Laredo, 4.0ho, TF999, Magnaflow exhaust, Yukon rear axles, Spartan Lockers, Posi locker, 3.5 inch springs, 1"MML, 1"BL, 1"shackles, trimmed fenders, raised flares, 35x13.50s.