Stop in for a cup of coffee

Well the 59 Apache is not going any place too soon. Oil pressure gauge was not working and got a new one installed and still no pressure.
Pulled valve cover and yep no oil topside. The engine has little miles on it since it was rebuilt and it runs like a top.
Anyone have a clue what could be the problem? It's a 235 6 that hasn't been started in about 30 years.