Champion radiator has been a popular option among the Mopar crowd. I have one in my Dart Sport and found one that fit my Aspen with a few tweaks. There are few core sizes to choose from but I believe there may be some radiator support differences as well. Jegs and some other independent sources sell them.
I have an extra new, early style from Mancini, but i't not cheap.
http://www.championradiators.com/