I want to try Somender's Grooves out on my DX head, for fun and because the head is already off and well why not because if I grenade the drivetrain it's an excuse to look for a D16A1 and transmission. Anyway what's involved is adding grooves like this http://themoportal.com/articles/singh/thumbnails/quench-groove_sm.jpg in the squish area to try and get the flame front to move more easily there and make the compression a bit more efficient. You can read more here if you like: Somender SINGH: Squish Zone Grooves: 20%+ improved performance of IC Engines -- 3 articles & US Patent Anyway as you can see in the attached pictures, there isn't too much squish area on our heads but I think I can put one right in the center of the squish area and aim it toward the spark plug, similar to this other one with a small amount of squish area: http://img291.imageshack.us/img291/4571/grooovesys6.jpg There is this tiny hole right where I would like to make my cut and as you see in the other attachment there's these 'dead valves' that do get moved by the cam shaft and I was wondering if this hole goes all the way through and if it will cause me problems. Will I be ok if I groove near this hole. Should I fill it with JB Weld or block it off somehow? Does the 'valve' actually actuate and move up and down this hole? Anyone know, I'm looking for thoughts. Otherwise I can just do two small cuts but just curoius if anyone can tell me about these holes and 'dead' valves.