Ford Contour fans are keeping my Dart's big-cam 451 cool at least in 86F temps. They cycle on and off about every 30 secs while idling at a standstill for prolonged periods.
I'm using a swapmeet copper-brass radiator, not sure what it came out of, just narrow enough to fit in there.
(If it's much hotter than that I won't be driving the Dart anyway, with no a/c!)