my current chevy 327 is cooled by what i think is a 3 core cj radiator and runs 180-185*. I swaped a 304 in place of the 6cly years back, it had a 2 core radiator in it and wasnt enough to cool it, I got a used 3 core back then from another jeep and it was fine, never got hot. 4 core would be better but 3 will be enough I think.