I have used a number of different fans and found the the pusher type to be not as effective as the puller type in cooling the car. I do not gun any mechanical fan driven by the engine directly (HP Drain). Have you tried raising the pressure on the cap for example from 12psi to 16psi. The rise in pressure will raise the boiling temp in the coolant so if the car does go to 200 deg. you will have more room to run slightly warmer. I live in on the coast of North Carolina and we see temp here of 90 to 100 deg. I( have a 502 in a 39 Chevy with a Griffin rad. Hope I didn't bore you to bad. Good luck!