Downflow VS Crossflow Radiators

There are pluses & minuses. In terms of cooling ability, no difference for same core area. With high mileage, cross flow cores can get silt build up in the lower tubes, as the stuff 'settles' when the engine is switched off & left for a period of time. Much like the crapola that settles in the bottom of the oil pan.
With an upright rad, the exiting coolant from the engine is on the high pressure side. At high rpms, pressure can force coolant past the cap.

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