Derale.com Has just what you are looking for. # 16789 is a daul fan, daul speed, fully adjustable from 150*-240* with thread in probe.
http://www.summitracing.com/parts/der-16789
I just bought one of their setups for my 408 in my dart. I was have cooling problems with my old downflow radiator with a pusher fan. Moved onto a crossflow with a puller and shroud this time around.
old setup
new setup