Thanks everyone for the info. Building a new motor for my 66 is a new venture for me, and I want to do one that is going to last for a long time, so sorry for all the questions.
What is a roller block? If I buy a crate motor, or rebuild this newer block, do I have to worry about extra ports for emissions garbage? I think I will stick with a carburator because I still like to work on it myself. Would there be any advantage to getting an older block, 69-74?