Drew,
Just last week I bought a 100% aluminum radiator for my '50 half-ton AD and it has already arrived. American Eagle Radiator is the manufacturer. (
www.americaneagleradiator.com) The quality is superb. The welds are high quality, the fill neck is full billet style, has 1/2" tubes, rated for 500 HP, has an intercooler, comes with brass petcock and a high quality pressure cap. Cost was only $159.95 plush shipping. 90 day no-questions-asked return policy.
I had been looking at swap meets for months and could not find any. Had also been on Ebay and only found over-priced used ones that were not gauranteed. I found this one and could not be happier. Fits like a glove.
Hope this helps you consider other alternatives.