Hello, all I just did a complete rebuild on my 2009 3.8 and am trying to add a REAL oil pressure gauge. I have done some searching and all I found was people using a “sandwich” adapter? Is this the only way to do it this? If so where do I get one? I do see an allen screw behind the oil filter can I use this hole? I removed it and it appears to be possible metric? Thanks again for the help everyone.