Hey Mr. P or anyone else who knows, what kind of fitting are you using for the large center hole that is the return to the engine after the filter? The one to the left of it on my engine interferes with the 3/8 to -10AN fitting as I screw it in, so I cant really even get it started, and I dont want to go grinding on the block there to get it to fit. Was wondering what kind of fitting is being used since the large hole is 3/4 fine thread