Low oil pressure?

I will say this. That very plug under the main cap was left out by my builder. Luckily he recognized his error and called me before I buttoned the engine up. You never know when a professional is having a bad day (we all have the occasional brain fart) By the way, it is pressed in and you have to remove the pump and main cap to access it. I just removed one from an old block I had laying around.