Have to disagree that the Chevy V8's is becoming dinosaurs.. and we have mostly Ford's except our Class C which is a Chevy. I've driven alot of V10's in shuttle buses and few RV's and the 6.0L in ours just as smooth, actually I think it's smoother, as the V10's IMO. The V8 setup makes for alot more room around the dog house which is a plus. Why fix wasn't isn't broken? Can't comment on the 8.1L can't see it being any different. The Kodiak chassis with the Duramax was on of the better shuttle's I've driven.