I'm talking about a 351M that was as worn out as any under-maintained, over heated, and poorly lubricated that can still run well enough to push an extremely clean 30+ year old Bronco body with a modified snow plow around. Heck, even the NP205 required some MASH type surgery just to stay in gear for driving it home on the highway after buying it. I've been lucky to keep it running the two years since buying it. It's getting replaced, even if it means rebuilding the good 400 I have in my 77 F250 to drop in - but a healthy diesel is always my first choice in a vehicle I plan on putting plenty of miles on and that will probably spend a fair amount of time idling or even doing some towing
After dropping the plow the other day, the front end was light enough to carry some higher compression