I know of a guy with a 360 in an A100 van who for about 1/2 a year was fighting something similar. He checked everything, verified parts as correct, pulley ratio, you name it, new aluminum radiator, the works, did every test imaginable, new and hi perf/flow everything, still ran too hot. Guy was at wit's end. He took another look at the new 6 blade MP pump he was using, assumed to be fine, turns out that after installing an 8 blade w/plate on the vanes it solved the problem. I know some here will disagree, and it may not be the case here, but rule out nothing.
