440 dart radiator...

Hey guys, i have a 1972 dart swinger that originally had a 318. I installed a mild built 440 years ago and have the original to the car 318 radiator in it with a flex fan and original shroud. Its always ran hot in the dead of summer here in the south with the humidity, mainly when sitting idling, but it still gets a little warm when moving. I dont want to have to swap radiator supports or hack anything up. What are you big block a-body guys using? Is there a direct bolt on radiator out there that will cool better that will bolt right in place of the original?
Thanks!