Don't know how big that IH dozer is.. likely pretty good-sized if you were clearing land with it! I'd guess that tryin' to get enough juice outta that pickup to crank the dozer woulda been a major PITA!
I'd sure like to get my hands on a 'ol D6 with a pony motor! There'd be he** to pay on the trees around here!!
I worked on my uncle's farm in MN during 75-77 and he had a JD 730 diesel popper that had a pony motor.
Man, every time I'd start that tractor, I'd be darn near white-knuckle figurin' that the pony motor would just blow right out the side!!! Whew, that thing would rev up and rev up and smoke, smoke, smoke!
The fuel switch would seem to be an easier route to go.. But, I can't help but wonder how the gas might raise a mess with the diesel fuel, engine oil and might be too explosive with the real high compression!?!
Ya know --- ka whang --- got a bent valve or three... or a cratered piston?
AKFish