Perhaps the radiator fabricator can help you size it. The standard automotive equvalent would be to add a row or two or three of tubes, depending on how many there are already and keep everything else the same if possible.

If you are stuck shoot me a message and I can inquire in the Caterpillar engineering department. I know some guys there.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.