That's what I figured... It'd be worth a look. Hopefully the op's motor hasn't spun a bearing yet.

Only reason why I remember was, a buddy had that happen to his Fbody after a trip down the strip. He got into the pits, and shut it off. Went to go line up again, no oil pressure on restart like 40 minute later.

 

So if that relief valve is seized i wont be able to move the cap on the spring?
Im pulling the pump and hoping thats the issue. The car ran for maybe 10 seconds with no oil pressure. Hoping its all well