Beginning with a "clean sheet of paper" build like this, you have the option of placing components anywhere you want to. One of the things I would want would be a rear-mounted cooling system. It would make little sense to me to make the thing more complex, with a radiator up front and plumbing it, then tolerating the heat in your face. I'd leave plenty of room between the powertrain and the cabin to fab up a radiator and cooling fan(s) arrangement, ducting air in from the top and/or sides and exiting underneath.

I remember years ago when Bill Thomas was racing Corvairs, they removed the sheet metal from under the motor to get rid of all the weight they could. What they found was that the motor overheated from air stagnating up between the cylinders. What happened was that air from underneath the car was creating a high pressure area under the car that was fighting the cooling fan. The fan could not push the air down between the cylinders because of the resistance from air pressure under the car. They replaced the sheet metal, eliminating the high pressure being pushed up into the cylinders from underneath and the car ran normally again. Since I suggested exiting the cooling air underneath the car, I wanted to make sure that you understand to make a completely enclosed sheet metal duct for the air to escape through and out the back of the car, without being stagnated by undercar air.