Contour Enthusiasts Group Archives Forums Modifications Duratec Performance polypropelyne glycol......reverse the radiator??

Roadrunner is correct. The idea is to hit the heads with the coolest coolant from the rad first and then the block. Keeping the heads cooler allows more ignition advance, thus more power. I think only the 350 in the Vette, Camaro and Firebird have it though.
As for running straight water, don't do it. The glycol and other additives also raise the boiling point and give corrosion protection. There is very little heat exchange when you've got steam in your pipes. Best mix is 50/50 if you don't get snow. I run 70/30 cause we hit -40 some days.