My last thought on this; I once owned a 440-6 pk Challenger back in the day. I had the experience of driving the car in urban environments (NYC /Washington DC) on occasion. Car of course had the HD cooling aides (26" rad, ps cooler, extra trans oil cooler) as well as the factory 7 blade clutch fan and factory water pump. Even changed out the thermostat on occasion to look for improvement in engine temp. Man, 440's run hot. In summer driving I was lucky to keep the engine temp under 220 (timing of course set correctly). The car also had a factory shaker with at least some cooler air entering the carb.
If you modify the engine for more power, it will need some help in the cooling department. I would at the least, up-grade the radiator. Good luck with what u decide to do!