If you do away with that front exchanger you could move the radiator forward, and that will give you the room you will need for the rear fans. It will also free up the restriction in front of the radiator and help cooling. And you might even have enough room for a
oil cooler if you want one. (not endorsed by cobrashock) BTW- nice location for your popoff. In the market for a good adjustible unit right now. Ta,Ta!!!!