Now this is IMO -
Ted, you over ride me if necessary,
"I will run 5 ½ qt of conventional Valvoline 10-40 with 1 bottle of ZDDP and a WIX filter for the first 20 min and then let engine heat cycle overnight, I will drain and inspect and cut the filter open, and then fill with the same mix for the second 20 min run. After these two runs I think I will use half a bottle of ZDDP.
I will fill the cooling system with a 50/50 mix, using the heater tube behind the thermostat. Is there any benefit to remove the thermostat for initial start? I’m not sure the thermostat in the engine has an air bleed hole."
If you have been following current tech, there are a lot of flat tappet cam/lifter failures. You need a quality break-in oil (say GIBBS) for run in. After run in, drop and fill with a high zinc racing oil and run for say 500 miles and then drop and use a street oil of your choice (higher zinc than common present street oil) . Now so-called RACING OILS have a very low detergent/dispersant package(s) as they tend to cause aeration of the oil at HI-RPM's. So it (let's say VALVOLINE VR-1 RACING OIL) has to have more frequent oil changes. I have never understood adding a can of additive as how many cycles will it take to mix with the oil if it does mix? The zinc has to be there for first fire. The oil needs to be blended from the refinery.
It has to first fire as pro-longed cranking will wipe the lobes of assembly lube. After that happens a second crank will be somewhat dry and you know where that will lead.
You want the coolant thermostat as the engine needs heat for the parts to expand and wear in. I would use distilled water. If you find a leak, it will be easier to deal with.
Just run her in and listen for noise(s) and watch oil pressure and coolant temp.
Simply put, you don't want a street oil for break-in.
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