Sudden Loss of Oil Pressure

One day while driving my little brothers 70 challenger with my 426 Hemi in it at the top of 3rd gear i bang 4th and the oil pressure dropped to zero.
I instantly shut the engine off and we towed it home.
I had the Dual line Milodon system with the swinging pickup. When we pulled the pan there was The Swinging pickup laying in the bottom.