So dumb I didn't want to put it in the topic. But here goes. How much anti-freeze should I put in my 68 350 with 3 core 23" radiator? I just put it together this summer and only put water in it so far. Would just draining the radiator and filling it up with AF be sufficient or do I need to get one of those hygrometer (sp?) things? Oh, this is in the St. Louis, Missouri area so I guess I should protect it down to about -10 and it won't get driven over winter at all.