I have a 70 challenger that originaly came from the factory with a 318, i now have a 440 in it. It originally had a 22in radiator, big blocks used a 26 in, but they had different core supports to accomodate them, On a 65 degree day the engine will over heat in about 2 minutes if i am idleing, driving down the road at 65, it stays cool all the time, however i fear that once it warms up to 100 that the car will constantly be overheating. I know i need an aluminum radiator, probably some electric fans too, however i need something that isnt 1200 dollars like BeCool's set up. Where can i get a good aluminum radiator, with or without electric fans for a decent price