I just want to thank all my 'hud' bros for their helpful advice with respect to the heating problems that I was experiencing. It turns out that the best advice that I got (which I started with), was to use an infrared gun to shoot the various parts of my cooling system, namely: the rad, the top tank, the thermostat housing, the exit and entrance hoses, etc. Guess what I found? When my gauge started to climb and reached 3/4's, a complete sweep of the cooling components strangely revealed that the engine was NOT over heating! However, aiming the gun at the sending unit proved the unit itself to be defective! In any event, I once again chose to thoroughly flush out the Hornet's cooling system, and this time also added a bottle of 'Water Wetter' to the 50/50 water-antifreeze mix. I learned of this product from another collector car friend, and it apparently helps reduce cooling temps by a further 8-12 *F. So with a new sending unit and some water wetter, my Hornet is back on track, even in +85 F weather temperatures. Again, thanks to all you guys for your helpful advice. Happy Trails to all, from a Canuck! ken