From what I have been told, the way to go is an 86 Chevette heatercore, that is what all these new radiators are based on because of the pressure drop. You will need to fabricate your own fan shrouds though. I heard that the heatercore will run about $20 at Checkers, etc. Danger Den wants $42.99 for theirs.
I do highly recommend the Danger Den 12V, you turned me on to that, but after all my research for my W/C part piece, I found that it was actually the best 12V pump you can get, and better than 99% of the other pumpsout there.