Screw in plug in the ports over top of the valley bolt. The plug is in it when ported, so when it comes out, the bottom is shaped like the port. Making it tough to keep it that way. Each time it goes in and out it has to line back up with the port walls, and because it's not flat the threads are tough to start. All I'm really saying is, if you have a wedge block, it'll work fine, just a better place to start with a hemi block, if you're starting from zero.