What year did they switch to overflow bottle radiators?

"That 3 row core will be tough to find I think."

StrokerScamp. I agree. Since the 2 core I have in it now seems to be OK I plan to wait until the summer and really test it. In the mean time I will continue to look for the post '73 factory 22" 3 core (if there is such a thing) and as you say go with aftermarket if I have to. I think I have other issues I need to solve that are making it run so hot. It's an old 318 motor that needs work and will eventually be replaced by a 360. But all that needs to wait for body parts and interior first.

Thanks for the help.