The two I put into my grove cranes I ended up buying military trucks and taking the motors. BMY series 5ton trucks. Iron planet is the new gov't seller.
I gave around $4,000 each (for the whole truck) , I think both had under 20,000 miles, one under 10k. They were mechanical pump motors, early 90's. The only difference is the military 8.3's use a different injector pump than the commercial motors. My trucks came out of ft. leavenworth ks., but they sell from different locations. The bell housings are different between auto and manual transmissions, but he should have his old bell housing.
Both trucks I bought ran and drove up on the trailer to come home. Pulled the motors and I sold the rest of one truck to someone building a mud truck.
I bought the whole trucks for less than I could come up with a motor, and nothing with that low of mileage, but I was close enough to go get mine, shipping might be a bigger expense for you.