In my big block cooling experience you have 2 options:
-A dual row 1" tube aluminum radiator. Be careful there is alot of junk out there. You are taking your chances with cheap chinese ones. Buy only from a reputable American manufacturer.
Definitely
not this one:
http://www.speedcooling.com/1963-196...r/prod_37.html
This may be a good option:
http://rndfabrication.com/CrossflowRadiators.html
The other option is a 4 core factory type radiator. After learning from my mistakes on buying a cheap foriegn aluminum radiator I decided to go with the 4 core I already had. My local radiator guy cleaned and tested it for me. He says it's the best you can get.