Wayne, if those buses were in the south, the prices might be high, but the market where you are may be completely different. I think that price for a bus is far more related to condition and maintenance for what it's actual value is, but scarcity and availability set the market rate for what you could or should pay. You don't say what models they are, but presuming the earlier one is an MC-8, then the 8V-92 is a pretty useful upgrade in power, but could mean trouble if the cooling system is stock. All else being totally equal, the later one, if it's an MC-9, could be better since the construction changed to more stainless steel in the frame structure with that model. But it has the 8V71 and potentially a lot less HP. Transmission also matters - manual or auto? Tires? Recent brake job? Up to date on maintenance of all the little air valves and hoses? Integral steering upgrade on either of them?
Hope this helps a bit. Probably doesn't, since it just adds questions!
Brian