stock replacement is all you need for those trucks.

they're HUGE radiators!

I'm running a 383 based stroker at 438 inches, 535 lbs of torque, 505 hp, and I'm using the stock radiator. with an electric fan from a jeep (19") it'll sit in 95 degrees, in traffic, and maintain 170-180 all day long. I have a 160 degree stat in it, and the fan controller is on at 185 off at 170.

the radiator will be more than enough to handle your stock motor, even if you've got the truck loaded to the max and are towing with it all the time.

cheapest radiator I've found has been at radiator barn.com saved me about $120 over the autozone price. Rock Auto might be cheaper though, especially with a discount code