Those oil plug stories bring back painful memories...my plug was missing from the back of the cam.

Ruined my season.

Although the engine had oil pressure (on the lower side) I had run as low before without issues. Because the lifters were not getting proper pressure, however, all kinds of wierd stuff was going on in the valve train. Once in a while, as it reached a certain higher RPM, it would hit a hard rev limiter.

When I decided enough is enough and time to swap motors, I decided to take the old motor (actually it was brand new) apart in the car. After removing the hood and disconnecting all the ancillaries, when I got the cam partway out I could see the plug was not there. Talk about pissed-off.

I simply checked the lifters and reassembled. Full oil pressure thereafter. Of course then it developed other issues in subsequent race weekends...