Ok guys here goes- bought this motor off a kid, got it home to find a cylinder filled with water and rusted solid- after sleeving the cylinder and replacing the main bearings and connecting bearings, complete rebuild and swapped it in the truck, pulled it once already to resurface the head and check the piston rings for damage I'm beat on this project. Before pulling the motor the first time I noticed the factory gauge dropping to 0 at idle so when the motor was out I swapped oil pumps and replaced the seal on the pick up, checked to make sure the sprayers were installed and I still have the same issue, I put a mechanical gauge on to get an accurate reading, once the oil warms up I have 10 pis above idle and basically 0 at idle. I crossed the main bearing number (3929017) with a STD Cummins bearing- can someone confirm this for me?

Now the area I'm concerned with is the filter housing, could the relief valve be stuck open or the cooler damaged or clogged? The gasket I got for it was slightly different than the stock ones I have used in the past but it was a Cummins gasket- basically the area between the two ports for the oil cooler feed and return is cut out in an "s" shape on most gaskets, that area is solid on mine and just has the two holes going thru it
The block is an 98 industrial Cummins block that I swapped the oil pan around on and stuffed into my f350