Does anyone else with an underdrive crank pulley have a heating issue? I've got the 6 1/4" March crank pulley and I'm wondering if the lower water pump speed at idle is contributing to my heat problem. I've looked at almost all the other recommended fixes. Car runs 175-180 at highway speeds but gets up to 215 pretty quickly in stop and go driving. I've got a flow cooler water pump, 3300 cfm electric fan with shroud, radiator upper and lower baffle pans, 2 row aluminum radiator, running 50/50 coolant mix with water wetter. Car has KRE aluminum d-port heads. I'm in FL and running a 20w50 synthetic oil. At 220 she starts groaning and I've got to shut her down.

My next test will be to change back to an 8" crank pulley to see if that helps any. Any other ideas? Four row copper radiator?