Percolation? Heat soak? Don't drive during summer??

RustyRatRod said

Geez guy, stop letting all these morons derail you. If you're trying to look at lower viscosity oil to run cooler, here's a hint....YOU HAVE SOMETHING WRONG. Your build is very mild, much like a stock build. You DON'T need a lighter grade oil to help it run cooler. You need to FIND what's wrong and FIX IT.

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I think he derailed himself. LOL.
From what I've gathered in the last relevant posts including yours, is this:
It does appear in the photos that the cooling system has no recovery tank and a universal top hose. Those a minor things that can help capacity and flow a little bit.
It's not running excessively hot.
It's not a loose build or have very high spring pressure but is in a hot climate. 10W-40 would probably be more appropriate than 20W-50 at the next oil change or purchase.
Something is up in the electrical system and still needs to be checked out sooner than later. That's far more improtant than worrying about coolant temps that are basically normal.