Glyptal engine paint??

There's another way to address the issue of oxidized oil without the hassle and with more side benefits:

Using a group III or IV synthetic that has far lower oxidation rates than regular group II petroleum oils makes more sense to me. Especially since you get the added benefit of much better viscosity stability (which allows a step lower viscosity range to be used for better internal parts cooling) as well as far, far better low pressure protection of the internal parts. My rally engines, which get hammered on for 10's of minutes at a time, don't show anything but clean inside surfaces at tear down once I made the switch to synthetics years back. And you can see a dramatic reduction in oil blackening with the synthetics.

YMMV....
.