Yeah, a 465 is a good size. A Quadrajet is a lot bigger, but works ok on a 253 because of the very small primaries. It's all about setting them up properly. A 350 Holley 2bbl works well too, but doesn't have the top end of a 465 or 600 4bbl because there are no secondaries.

As I said, I have the 600 and a huge supply of jets and secondary springs, so when I do get around to doing it, that will be my starting point. It goes real well at the moment, so I'm in no hurry. One rainy day sometime in the future I'll have a play with it.