As many of us have found out, the original radiators are getting very expensive. Fortunately aluminum radiators are still pretty reasonable.
Be aware there are two different style radiators used in the 3A. Earlier ones use a bottom mount setup, and later ones (after serial number XXXXXXX?) are mounted to the grill by bolting on the side of the radiator, side mount style.
Carl and Calvin installed one of each in this thread. It is well worth reading to see just what sort of problems you may encounter. The short version is that the bottom mount Champion Radiator is easily installed, the side mount is a huge project and will NOT fit out of the box at this point.� �� �� �http://www.cj3apage.com/cgi-bin/yabb2/YaBB.pl?num=1376456433
There is also a Mustang Radiator that Nate installed in his V6 equipped flatfender, with good results. His post about that is here:
http://www.thecj2apage.com/forums/aftermarket-aluminum-radiators-purists-look-away_topic21436.html?KW=aluminum+radiatorNote that the radiator is a good fit for a v6 equipped 3A, and is NOT for the stock setup.
Any mention of radiators should also contain a link to Lew Ladwigs radiator rebuilding thread. If you are adventurous and would like to try out your soldering skills, it is doable and can save an original that is not too far gone.
http://1945gpw.com/c-92-G503_WWII_Jeep_Radiator_Rebuild_Restore.aspx