How much does it take to cool these things? It is pretty well stock with a 1406 Edelbrock carb and a 4 core Champion aluminum radiator. It seems to cool fine at first for about 4 miles but then just like it can't keep up and it will slowly clime to about 220 on a 90 deg day. The weird thing is even when I stop to let it cool down, it really doesn't do that well either. I have sit and idle with electric fan running full bore it takes forever to cool. Timing is about 15 base and 40 at 2500. I have my heater hose looped right now, could that be cavitating the pump at all , shouldn't be so complicated. The carb was running lean so I swapped the primarys and that seemed to maybe help a little, down to 210 but its a different day too. Changed thermostat right away and that did not help at all. If my radiator can't handle this thing, you'll see a 348 for sale and a 6.0 put in my 53, I've come to the part of my life where I grow tired of fighting things