[VeryTangled]

As to the cooling question... My 36 runs with plenty of coolant in the large top tank, like an inch over the tubes. In 10+ years nothing has ever come out of the rad cap area or overflow tube. Assume I'm charmed with that combo.

My 35 with a very fresh redone stock radiator (small top) will not tolerate fluid above the tubes when cool. Freaks me out, but the expansion brings it up over the tubes while at operating temps and it doesn't shed fluid.

That '35 with the old engine and rad (I replaced both last fall) also didn't like fluid above the tubes. I kept topping up, and it kept pissing it out.

Since that combination is gone, and I have a fresh engine and fresh rad, I put fluid in, and run it. About 1K miles on the new combo and I stopped checking the level cuz the gauge never goes over the N in NORMAL on the glass sight temp gauge and nothing is coming out at the radiator cap area or the overflow tube.

Hope this helps.