I'm going with Jerry on this one. While the 327 and 350 can make to power to move a bus, really what you want is an engine that makes lots of torque, preferrably down low in the powerband. Back when i was in school, we still had gas powered busses, mostly IH, but a few were GMCs. The Jimmies were all tall-deck 366 and 427s. Same goes for the Kodiac trucks that the place my Dad worked had, no smallblocks, all tall-decks. You may find tit more economical to run the big block over a smallblock in that application, simply because the biblock will make the power where you need it without having to mash the gas to get it do so.
