Well James I'd take the rig with 40K vs. over 100K too, especially if its a gasser. Very few motor homes will get used into the 100K club, whether they are diesels or gas, the exception being perhaps high end high dollar DP like Prevost or Newell's that will go into the hundreds of thousands of miles. Newer rigs from 2000 or so are almost exclusively Ford V10's as GM got out of the RV business. Don't forget to take a creeper with you on inspection to take a good look underneath the rig. Oh, by the way, if I fill my water tank up with a high pressure faucet, about 20% or more of it will flush out of the overflow hose. When added nice and slow, I'll get a full tank that will last me at least a couple of days more with out water hook ups. Could be the same problem facing the rig your looking at and the owners never figured that out.
One last thought is to check the spark plugs out on the 460, they did have an issue with them rusting into the blocks. Good Luck and welcome to this forum.
