I'm having a little trouble keeping my old truck cool on these hot hot hot summer days or while sitting in traffic. The temp really wants to creep up. I've got a fan shroud, the rad was re-cored a few years ago, I've got a big 7-blade fan, water pump is new with the anti-cavitation plate, the coolant is a little on the water side of a 50/50 mix but not too much with Water Wetter, t-stat is new and works properly, original factory water pump housing, and the viscus clutch is new and a heavy duty unit.

I've been throwing parts at it and nearly everything I've done has helped but nothing has solved the problem. I'm wondering exactly how far back does the fan and clutch need to be from the radiator? I can squeeze my hand between the fan and the face of the clutch and that's about it (so an 1", maybe 1.5"). Is that too close?