The oil pump is the one that was in the engine when I removed the engine from the car the first time. Now...for some reason I'm beginning to remember, (but old timers is hitting me pretty hard right now), I'm thinking that the cam freeze plug came out and instead of replacing it, I RTV'd it back into place. 'Cause there's RTV around the cam plug. I just don't vividly remembering doing it. The RTV is the same color as the rest of the RTV I used on the gaskets.
It is a good thing you pulled the engine then. You will need to replace that old RTV'd Welch plug with a new one as it needs to be an interference fit to hold that much area against the possible maximum oil pressure generated. You don't want it blowing out and pumping your engine's life blood onto the road way as it bleeds to death.
What I do in my builds is to install a Holley Safety cut off switch (intended to kill the electric fuel pump if your car turns turtle and you find yourself upside down with the motor sucking air instead of oil). It will disengage if the oil pressure falls below 5 PSI cutting off the fuel pump to prevent a possible fire. I use it to save a motor by killing the ignition if I loose oil pressure (think of it as a self acting idiot light that that does something useful instead of just glowing red to tell you that you just lost a motor).
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While you are holding the ignition switch on start the switch is by passed and the starter motor will generate more than 5 psi as the motor turns over. Once it is running and on the ignition run part of the ignition switch you are protected if you every loose oil pressure.