I had a 5-blade fiberglass flex on my 66 Chevy Van with a in-line 250 out of a 79 C10. I was driving 75mph and the engine overheated. Reportedly at high rpms the flex fan flattens out and doesn't pull much air through radiator. Found out the aluminum timing gears needed to have been heat treated when put on instead of banged on incorrectly. As such, things got messed up, my cam started walking, causing the timing to keep jumping, roll pin in distributor gear to shear and eventually ruin cam and lifters. Anyone using electric fan, if so what brand? If Not, are you using a factory fan and how many blades? Thanks