if you have one of these engines, i feel sorry for you! they are the weakest, most trouble-proned engines ever put in a 4wd vehicle!
for years, i worked for the army in depot and battalion level maintence and no engine gave us more problems than the engines in M715s. it's been many years since i've seen one and good riddance!
a friend, who had a pristine M715, fought his for several thousand miles before he got an adapter and installed a 250 chevy six. after that he had many trouble-free years of service out of it.
the transmissions, transfer cases and axles are almost indestructable, so just about any engine you'd install would be better than the original!
a few years ago, out in texas, i met a fellow with a diesel engine in a surplus M715, he also claimed to switch because of early original engine failure.
others might have better exoerience than i've had, with the kiaser ohc, but i haven't met one!
