I've searched this forum and found the port on the relocation block labeled "plug" is a standard plumbing type plug but never found a size. Is it a 3/8" plug? I was digging around and found a 3/8 plug will go in a couple of threads but gets pretty tight. I want to ensure I use the correct size to avoid gauling the threads on this thing....Can someone give me the skinny on this port?

Thanks,

Casey