Oil pressure problem-Excessive PSI

[ratrod67]

I'm having some Oil pressure problems with my 509ci BBC. I had the motor running fine in a 71 Camaro, sold the body and installed the motor in a 72 truck. No changes to the motor at all. Started the motor for the 1st time in the truck and noticed my oil pressure was pegged at 100 psi. Shut it off imediately. Looked on the ground and saw about 5 quarts of oil. Filter was tight so I checked the oil filter adapter. Looked ok so I reinstalled it and tried again with a new filter. Same thing. 100 psi and oil on the ground. I figured the filter got bumped or maybe the adapter was bad so I went and bought another. GM parts guy said to install it with no RTV or gasket. Oil filter adapter straight to the block. Started the motor and same thing. 100 psi and oil everywhere. It's leaking from the top of the filter. Not spraying but like it's overflowing out and falling straight down. I made sure the bolts weren't too long and bottoming out and it's not coming out from higher up the motor. I had someone else start the truck while it was on jackstands and watched it flow out of the top of the filter. Also made sure I'm using the right filter as well. The adapter I'm using is part # 3952302 and filter is a Fram PH25. Any ideas?