Turns out the plug was aluminum. My brother and I are thinking someone used red locktight in a number of places they shouldn't have. Thanks for the info on the bolts wasn't sure.No metric hardware in the intake. It's most likely cause it's a steel plug in an aluminum intake for it fighing you. Best thing for those are aluminum plugs for the likes of Summit or Jegs, that what I did. Instead of fighting that plug if you don't need to try drilling it out at the dimple bu the water neck. I'd stick with the stock size thread sender for it (3/8" NPT) unless you already have a 1/2" NPT tap.