Zack Any contact point will make heat. Really the worst thing is the valve springs. You open and close at over 60 per second and you make heat. I only speaking for my motor builds and believe in keeping
oil in the heads to help cool the springs. The splashing around helps the rest of the moving parts too. I have about a 13 quart system with
oil pan, cooler lines 3 quart accusump and what doesn't drain back into the pan.
Some motors have spray bars in the valve covers for extra cooling and because of running very high valve spring rates of 700+ pounds. I think Nascar also uses them. It's like turbo diesels have oilers that spray the under side of the pistons to help control heat and lube the pin, rod end and piston.
A thermostat is a better idea to run than just a cooler. heats the
oil quicker, also cools it off too. My only concern to amount of flow through this housing and pressure limit. Cold my motor is in the 125-128psi range. Once it heats up the psi drops the the 70-85 psi range. A normal street motor doesn't need a lot of extra cooling. Track cars need this alot more. Rick L.