Anybody have underdrive pulleys for their 2006 5.4? I have a 2006 f150 4x4 5.4, it's mainly used as towing vehicle pulling heavy loads, pretty soon (if not already) it has SCT tuner, granatelli CAI and mass air flow sensor, and flowmaster muffler. Worried about engine cooling on the long hauls.... i purchased underdrive pulley's from rpmoutlet (didn't receive them yet).....