64' Dart Radiator

i used a stock 22" radiator out of 70's a-body in my 64 and trimmed the core support to open it up enough to get the entire core some air. oh yeah, its got a transplanted and slightly warmed up 360. That didn't really help at all so i had the 22" rad re-cored to a high-capacity core, its great when your on the road but it will start to creep up when sitting at idle. Now that the weather is getting warm again I'm going to have to do something, just don't know what quite yet. I think the first step will be ditching the flex fan and trying to locate a good steel factory fan. (Motor didn't come with one). If that doesn't help I guess I'll try one of the Flow-Kooler water pumps. Anyone have any experience with those?
-Tim