Electric VS standard fan

Right now have a high flow 180 thermostat installed. I've tried a single 3000 CFM fan with offset shroud, dual 12" fans and the dual 16's--16's wouldn't fit due to water pump pulley clearance. I can't fit a fan/clutch assembly with only 2.5" clearance and could not get the system to fit due to 3.5" clearance needed for the fans. Engine and K-frame and trans are all original ---only thing I changed is the radiator and A/C compressor. I think the radiator is 2.5" thick--factory rad is 1.25 I think--I'll measure that tomorrow. 2.5" is the clearance between water pump pulley bolts and radiator. Link to Spal USA--these were the ones that didn't fit -already upgraded the alternator as these fans pull 65A and were the baddest of the fans they sell--I might give summit a call. I'll post pics of the shrouds I made for these fans tomorrow.
http://www.spalusa.com/pdf/30102082_SPEC.PDF#view=FitH