I got a price today on a #730 2 row Aluminum radiator for $220.00 + shipping from AZ.
Bryan McCulloch @ alumrad.com says this unit cools very well in the hills of Arizona especially on haulers w/ 454's totin' camper trailers and boats in the hottest part of the summer w/ stock cooling fans.
It has a 19" x 28 1/4" core that directly replaces a stock 2 or 3 row brass radiator.
Good luck. I think I'll order one soon.