I recently blew my 454 big block and swapped it out for a lil 350 with a mild cam. When we got the motor it had been sitting for 2yrs still attached to the shipping crate and covered with plastic. I had the cam pulled and put a bigger cam in and some head work.

I've ran the motor 6000 miles now with very lil issues. I store my truck every winter and today came the day to store it. The truck had already been sitting for 5 months because I was gone for a while. I started it up letting it idle for a good 45 min when it sounded like the lifter collapsed, which I found hard to believe. My oil pressure gauge was at 0, so I shut it down. I used a manual gauge to check it and I still had 0 psi at idle. I Rev'd the engine and the pressure shot up to around 45.

I pulled the distributor and turned the pump with a drill using an old distributor shaft. The pump turned freely and the gauge never moved, I didn't figure it would. I took the gauge out leaving the hole open and turned the pump with the drill, oil cam out in a steady stream.

Im stumped on why a new engine with 6000 miles has now lost oil pressure.

I came to these lil conclusions. Possible spun bearing from sitting for 2yrs and then the installation of a different cam. Maybe it spun just enough at first start up and now it spun more.