This is a photo of the port side facing the rear, I believe that's called the flywheel cover. I don't this the oil is coming from that seal, but curious, is there oil behind that cover?
It's pretty easy to create a valve cover oil leak back there, I did it. Try to get the valve cover gasket perfect and see if it still produces oil. The oil pressure sensor is back there too. If it's coming from the rear area around that flywheel cover it's a project to repair., so check the things that can be serviced more easily first.
If no one has worked on the motor suspect a valve cover gasket or a rotted cover. Other places are the dist gasket, and the oil pressure sender either on top of the motor or located just above the oil filter.If you have an electric fuel pump, there is a pressure switch located in the same area.
Just had the top end of the motor rebuilt. Went down this evening with a black light to see the dye. Coming from the front and the rear of the intake manifold and from both valve covers
Now that we have all the needed info, you will have to remove the intake manifold, clean the rtv off, wipe with alcohol .
Place a 3/8 ths bead of sealant on the front and rear of the block.
If its a vortec manifold ,use 4 guide bolts /rods in the 4 corners
install manifold and ONLY START THE BOLTS, do not compress the rtv , GO TO BED. COME BACK TOMORROY
Tighten bolts to spec and install the rest of the components, make sure the dist gasket is in place too.
They are a very respected marina on the river. I don't want this to turn ugly because the marina is 7 minutes from my house. Very frustrating! But the owner is an absolute gentleman, so I hope I have a snowballs chance in hell