Thanks for the information George and Larry! You guys are great! BTW I did the cooling system header tank conversion along with all new stainless steel pipes, proper 180 thermostat, 195 fan thermoswitch, a new 4 row, high flow, louvered brass/copper radiator core, and a 4.9" water pump pulley per George's write ups. I also rewired the fans with relays and installed new Pusher fans (cool cat corp) Last week I was idling in Pasadena when it was 99 outside with the air conditioning cranking, and the water temp via an IR gauge at the swirl tank was 212f. Radiator outflow was 190f. Car didn't boil over and everything seemed perfect with the fans blowing. Once again thanks for all the expert advice!