I freshened up an 86 305 with new gaqskets and seals and oil pump to put in my 85 Z28 (Same engine codes). It is the LG4 4bbl engine. I did my intial start up last night and it sounded great and had a bit over 30 psi oil pressure. After running it for a couple minutes the oil pressure dropped to zero and the engine started to sound like poop. I shut it down and it still rotates. What do I do now?

 

Pull oil pan recheck oil pump.

 

How is the pickup tube/screen/filter held onto the pump?

 

Maybe it blew a gasket... I had an issue with an oil change recently where the rubber gasket didn't come off the housing and I didn't notice... replaced, 2 gaskets, oil everywhere. Is your oil level fine?