Hey sublimeswinger-
Thanks! The guy I bought it from said it was a 318, and due to the light blue paint on the block, I'm inclined to believe him. We'll find out for sure on tear down. 65's originally came with 273's.
It's funny, I was kinda hoping for a Leaning Tower of Power /6 instead. Dreams of an ethanol-fueled, 14:1 CR'ed, HyperPak'ed and Fuel Injected LToP keep dancing through my head:idea1: But, that'll have to wait for another thread :)