My 422 smallblock build

Run an 8 vane water pump, move that coolant! Keeping the coolant in the block longer to draw the heat out is hogwash. Less restriction faster flow.
IMHO, the PRW pump is the best I’ve seen yet with the actual volute pump body and the cast iron impeller. That is, except for tapping the cover and using a pair of -16 lines to an external electric water pump. But we’re going way outside the realm of what would be needed almost anywhere with that Frankenstein rig.