Early cudas 64-66.. might check one out
As for what to look for its the same as anything else, pans and frame condition etc. Beyond that, missing trim/emblems/interior pieces can be pretty pricey because of the fact that there arent near as many aftermarket pieces as the 67 and up fish. Not all, but most of the 64/65 parts are the exact same. The 66 has a lot of 1 year only parts so anything thats missing will just be a little harder to find and probably a little more expensive. I can tell you from experience that doing an Early-A is GREAT!! I get a little extra satisfaction with each thing I cross of my project list because of the extra challenge as opposed to a later A and even more so a chebby. Good luck and let us know how it goes!!