Good old pre-80s GM buses. Can't beat them with a stick, can't kill them. I noticed you don't know what engine is in it, if you'd like to post some underhood pics of it, I'll be happy to help you identify it. More than likely it's a tall deck 366 gas V-8, but other options were available.
I tawt I taw a putty tat! *peeks*
I *DID* tee a putty tat!