So boys I didn't wanna make this post but this engine has got me baffled beyond baffled. First off let me go into details on the engine. I started the motor for the first time couple weeks ago and had low oil pressure. Immediately pulled it and replaced some things. All clearances are in spec, rotating assembly balanced and everything in the bottom end has been triple checked. There is only one plug that ford doesn't supply in the block and that is the one behind the water pump which was plugged by us properly (the second time I pulled it) with a 17mm plug. We started with a 16.66mm plug and then decided we got the 17mm plug why not double plug if it'll fit. Sure enough the 17mm plug fit and was extremely tight over the 16.66mm plug. So the plug that goes behind the water pump has been for sure plugged. The new oil pump I warrantied for another new pump Replaced the o ring in the oil pick up and cleaned the pick up replaced the oil pressure switch Now basically the 4 things I could ever think of it being have been replaced. We put an oil pressure gauge on it and cold started it and it shot to 60psi then teetered off to 40...30.... then to 20... then I didn't want to risk it once it dropped below that as she warmed up. Thinking we might possibly have a faulty gauge we put back in the oil pressure switch and sure as shit she popped up low oil pressure once again. No oil leaking anywhere externally. Now I am at a complete loss. I am about to pull the motor for a third time, which isn't the end of the world, but I can say I am pretty damn tired about it. Going to put ARP hardware in the bottom end and do a couple other things while I am there, but if I can't get this low oil pressure thing figured out I don't know if I am going to even have oil pressure after stripping the block back down to bare and having everything checked for the second time after being built originally. Only thing I could possibly think is some how the cam phaser seals to the cam sprockets because those have oil pressure on them for the VCT? I inspected them like the book says to do and everything checked out and went back together smooth as silk, but I will replace them anyways this next go around. Basically at a loss and looking for recommendations.