Hey Gang, I have noticed alot of Cooling System advice lately. This is the approach that I have used with much luck: 1) A 160'F 'stat with a 1/8 hole that I drilled in it. 2) A 50/50 mix of Prestone and H20 3) An aux transmission cooler so that scorching-hot tranny fluid is not running thru my lower rad tank,adding more heat to the radiator. 4) A "hosing-out" of my radiator fins now and then with a car wash power sprayer to rid it of bugz,etc. An aftermarket Water Temp gauge has been added by me so that I can cross-check the temp with the factory gauge. I have never seen temps go passed 200-210,ever....even on 90'F+ days sitting in traffic. No,I don't have the heavy-duty radiator. It helps to have a properly working clutch-fan that will lock-up when thingz get too hot. It also helps to have a clean cooling system to avoid hot spots. If your temps are hot as per the sending unit in the front of the block by the 'stat housing,you could very well have localized hot spots in the back of the block or heads hot enough to bake ceramics. Steve from Albany,N.Y. <--1st time checking my mail in 3 days. '75 Imp 4dr <--a coolant system flush and fill done last fall. '79 440 powered 35 ft RV <--a HUGE radiator and front heater-core...and a big heater-core in the back-bedroom fed by 50 ft(25 supply,25 return) of 3/4 copper pipe. It sure does hold alot! _________________________________________________________________ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx