Radiator

IMHO

Copper brass and the cooling level designed for your engine.

There is much more to cooling than 3 core or 4 core.

1. Do you have the correct water pump for your pulleys
2. Do you have the correct radiator for your water pump
3. Do you have the correct fan and or thermostic fan clutch for your application.
4. Do you have the OEM correct fan shroud. If it had one for the application.
5. Are you duplicating standard cooling A/C cooling or HD cooling

Each part of the system has to work with the other correctly to not have issues.

The factory was able to cool a 383 /440 with the propper components.

Also don't get hung up on keeping the engine temp to 180 deg under ALL driving conditions, it will make you crazy.
Good luck