Id be shocked if it was, in fact, an 'e' 466. Those came out in 94 at the earliest and it might have even been 95. The at545 is also not the best tranny for a 466. If you can, an mt643 had many advantages over the 545. Either way, that bus is a terrible deal. You can do better for less. Any seller who says a leaking head gasket is an easy fix is a either an idiot, a liar, or both!
Patina enthusiast and professional busman