IMHO
Copper brass and the cooling level designed for your engine.
There is much more to cooling than 3 core or 4 core.
- Do you have the correct water pump for your pulleys
- Do you have the correct radiator for your water pump
- Do you have the correct fan and or thermostic fan clutch for your application.
- Do you have the OEM correct fan shroud. If it had one for the application.
- 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
