We sell Thomas buses. It is common to see the Econoline front small school buses coming in with 300,000 miles and more on the V10 and still running. I don't know about the 8.1, but I know that the V10 is as good a gasoline engine as they get. Part of the reason is a very stiff block. The cylinder head studs are screwed in at the base of the block with the crankshaft having 6 bolt main bearing caps (4 on the cap and two cross bolted). With a little breathing help from Banks with their excellent intake and exhaust kits, the gas V10 is really not to bad of an engine so long as you don't exceed 26,000lb total weight on the motorhome. Personally, the V10 is the only gasoline engine I would consider. Good Luck, TomC