i've got a 16" Hayden universal fan with a 3 core radiator out of a Cutlass and it has no problems keeping things cool despite not really moving a lot of air.
i was going to run that fam on the stock radiator, but i couldn't find a top plate that wasn't built into the fan shroud so i swapped in the bigger Cutlass rad that i had laying around with a top plate from another Cutlass in the junkyard.. i'm pretty sure the small stock rad would have kept it cool with that fan since i had a similarly sized radiator with an electric fan out of an 86 Celebroty in my 355 powered 71 Nova and that thing never got over the thermostat temps..