1st like your hotrod. Where you have the radiator now will never work. Air will always be a problem and your fan what little air its pulling is hot air. Why don;t you just mount the thing where it belongs ,make a nice cart oriented grill and headlight piece and solve the heating problem. Looks like you have plenty of room. All the eyes are going to be looking at the cart gorng down the road,not the drivetrain.Take a look at the Baha ottroad trucks,their radiators are in the back but still mounted higher than the engine. One thing that might help would be to find an older V-8 Mustang radiator. Smaller ,taking up less space but will cool your engine fine.