Radiator and Fan clearance...

Careful on the flex fans, as I noticed that most of them are only rated to 4000-5000 rpm, which seems kind of pointless to me. That's why I chose the one I did, as it was rated to 8000 rpm per Mancini Racing website.

I'm running that fan on a 1/2" spacer and it left me plenty of room in front of the radiator. Basically I bought a 1/2" and 1" spacer and chose the one that positioned my fan to the shroud so the blades were half in and half out of the shroud. That seemed to be the consensus on fan location to move the most air through the radiator. Works well on mine. You can hold your hand in front of the radiator and feel the air flowing through at idle.