Very Low Oil Pressure in New Engine

Okay, it was opposite with the plug in backwards,

"OK, I've recently been made aware of an issue with the Melling high volume oil pumps. It would appear that the cup plug for the pressure relief spring has been installed backwards in some pumps. The cup portion should face the spring and be pressed in just far enough to install the cotter pin. My pump came with the plug pressed in with the cup facing outward towards the cotter pin. mshred installed his back in the same way (as did I) and he ended up with over 150 psi of oil pressure just priming his engine. "