Newbie needs help decoding!

Thanks for the reply. Is that the way most A-body enthusiasts look at it?
I realize V-8s are worth more, as a rule, but have always respected /6s.
I am a nut about originality and wondered if I had missed something here. Perhaps the block was replaced with a 65 and was stamped or re-stamped to look like a 64?
Or the factory sometimes pulled newer blocks intended for the next year?