Whatever you choose, it will be a huge step down from the copper/brass radiator the truck was born with. I'd suggest getting a 4-core copper radiator out of a late 1970's to mid-80's 3/4 ton with a big block engine and doing whatever it takes to make it fit the core support. Mount the electric fan in the passenger's seat to keep yourself cool, and let that big honkin' V8 drive the fan like it was intended to do.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!