FWIW a lot of tracks don't permit running glycol coolant as its slippery and bitch to clean off asphalt when spills occur. Consequently many guys that track a lot run just a water system with a corrosion inhibitor.
Aluminum radiators are prone to galvanic corrosion and Fluidyne recommend 'No Rossion' which is what I'm using. There are also 'water wetter's' that aid water to metal contact through surface tension modification that can help lower your coolant temps.
I have my '74 original kicking around, good condition if anyone needs one at a fair price.