I also run a Summit radiator: http://www.summitracing.com/parts/sum-380428/overview/
This one fits my 22" core-support opening perfectly. I run a Summit flex fan: http://www.summitracing.com/parts/sum-g4917
with a custom made aluminum shroud. My motor is more in the 500 HP level, but it runs cool with no issues. I've thought at times of adding an electric fan, but the current setup cools just fine. I'll see if I can find a picture of the setup.