I have a 1972 MCI7 with 8V-71 and recently converted to automatic, bought as a seated coach. Now almost finished conversion ( 6 years off and on).
1) Have someone knowledgeable check over the bus first. Look for signs of rust. There was some stainless used on the MCI 7s, but there is still lots of regular steel that may have rotted away over the years.
2) Unless you have the documentation in hand to prove the engine/transmission are rebuilt, expect that they are not rebuilt. I think every coach sold has had the powertrain rebuilt recently
( now where did I put those invoices??)
3) Tires are ex$pen$ive. Check the date codes on them. Look for cracks.
4) If its a standard, be prepared to learn how to drive it. It doesn't shift like a Chevy 1/2 ton. There are some good articles on 'how-to' on this board...use the search function.
5) Is this already converted? or still a bus? The market is in the tank. You may be able to go up a bunch of years by purchasing a coach already converted.
I really enjoy our bus, and with the automatic it's even a pleasure to drive. Keep the other half happy and involved, and don't wait til it's done to use it....go for a weekend( or even overnight ) as soon as you have the basic systems in place, and frequently after that.
And please, please ask on the board about anything you are unsure of. There's almost nothing that you will do or try that hasn't been done or tried already, and most of us are willing to share our experiences with whomever asks.