20w50is very old school thinking.
I would not recommend 20w50 for anything other than a very old school, and archaicly, built engine.
Run the thinnest oil that will still give you goo oil pressure. I typically run 10w30, max.
I still haven't installed an oil pressure gauge which is crazy I know. It came with an electrical gauge since it was an AHB, but I didn't re-install when crate engine was put in, so I don't know what oil pressure I have currently running Valvoline 10W-30. Again, I know I have GOT TO put an oil pressure gauge back in! I figure my engine is kind of old school, not being high tech tight tolerances modern day engine. Yes, roller cam, but still not the tight tolerances of today's modern built engines, no?
