Originally Posted by RonR
If it runs its worth about 2500-3500.
If it does not run, its worth about 1500.00
Seems about right. I repowered 8 years ago with John Deere in Port Townsend, WA. The 555's were running take-outs (1950 hours, instant start, no smoke) and from memory I eventually sold them for $5000/pair. I removed them to provide access to replace leaking fuel tanks and figured it was a convenient time to repower.
In any application they were durable engines in low-medium duty. In trucks if you did not flog them, make them 'lug' a lot, run at high rpm and loads (they were rated at 3000 rpm) then they lasted. For trawler boats they were fine, for sport fisherman's, not so much - for the same reasons. In trawlers they probably operated at 1600-2000rpm and were effectively baby-ed and would last a very long time.
The key for boats were to have SS exhaust crossovers fabbed in the PNW (about $12,000 10 years ago), heat exchangers/ exhaust manifolds were ok. Raw water pumps were pricey - back then $1250 each. Parts availability, marine specific items mostly, was not too bad due to after-market suppliers. They are quite an old design now, so engine internals from Cummins may or may not be tricky to get and won't be cheap. But they did not fail catastrophically very often at all, and there are enough old ones around to source stuff for rebuilds. In boats, poorly designed exhaust mixer elbows, that allowed water to run back into the turbo if they failed, was another issue. The PO of my boat had that happen to one engine.
They were very common in Ocean Alexanders in 50 ft range, and similar boats. At the time Cat 3208's were popular also, and builders used one or the other. There are still lots of boats for sale with 555's in them. While some buyers may be scared off (people either loved or hated the 555's, but there were lots of myths propagated that had little substance) if they have been well maintained a savvy buyer will regard them as a win.
The problem is, it might take a while to sell and then they are big and heavy to ship. One guy in Maine wanted to buy my engines as he had a pair and one had failed. But try as he might, the cost of shipping from West Coast to East Coast was 50% more than the engine price. The guy did a lot of shipping of car-type stuff and felt it was nuts, but it was going to need a substantial crate/pallet and forklift at transit points etc.