Thanks for the info Moose/Ed! I still get parts ect at cost from my buddies parts store(an AC/Delco/GM inventory), so the extra price of the good stuff is affordable
There used to be a similar old product (water wetter)from Siloo that 1/2 the dirt track cars in the 60s-70s at Dodge City ran it. With small cubic inch limits over boreing, high rpms and small radiators...they were after any advantage. I asked my nieghbor about it, he had a '55 stock car and his parts house carried it. Yep he said it lowered the "service tension". He said with straight water it was usually good for around a 15° temp drop. With anti freeze it was only about 5/10° drop.
Dad ran it in their super modifieds (usually run 301 ci)until his buddy came up with the dry ice trick. He would go pick up a 30 gal drum of it on saturday morning. I don't remember if he was putting any in the top tank, but he built a trough that the lower radiator tank would bolt down thru and pack the dry ice around the bottom. Worked better than water wetter anyway