Cooling capacity

Update- I drained the radiator, then added 1 gal of straight antifreeze. Filled to about 1/4” above the tubes, then started the engine (no rad cap). When it got hot (160 thermostat) I added back some of the mix I drained. I revved the engine, watched the flow in the rad, added till it is now about 3/4” above tubes - 1” from filler neck. Put the cap on. Cleaned and drained the puke can.

5 mlle test drive, about 50 mph where possible. No problems. The final mile, I went 5-10 mph for parade conditions. No apparent problems. No puking. When it cooled down, fluid level right where I left it.