Sorry to appear snarky, but if you are looking at 24 year old motorhomes, you are looking for problems. The only questions are how many and how serious. I do certainly agree that that Detroit 8.2l would give me pause - or maybe even shivers - the main consideration in any rig that old is condition and how well the previous owners maintained it. A well kept old coach with some less-than-desirable components may still be better than one that has the right stuff but years of neglect.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL