Dave , a closer look at the 4 valve GSX head pictured above shows hot only the V shaped groove at the exhaust valves ,but the small grove leading from that  down the ridge between the valves to the sparkplug.  The large grooves provide the swirl as the piston rises, and the small grooves provide an accelerated path for the flame front , back to the quench zone to insure combustion in that far area , as the piston drops .  Mike's quench area is .060   not  ideal . While adding the grooves may reduce Mike CR slightly ,this may not be all bad, when you raise CR by one point from 8.5 to 9.5 you gain about 5% more power ,but raising it from 9.5 to 10.5 you gain only about 2.5%   . Mike 's present CR is 10.41 ?  He may still have 10:1  even with the grooves , and reduce his 245  static CR to somewhat closer to 200 psi,  something the stock piston(casting) can handle . The motor should run cooler , and is another thing that should be considered , higher CR ,comes with higher ignition/head temperatures.

Dave , why not go to Singh's website and look at a finished head ?

Just type, sommender singh , and hit search. you'll find plenty of pics  if you llok down the page to the gallery . You might also look up test results of the Singh grooves by Garrett Robert Hering.-
                                     
     
  http;//www.heringg.com/singh

Keep in mind that this test was performed on a two valve head,  GEO motor,  with one groove and one small quench area. I have faith that results would have been better if a 4 valve head motor would have been used.

I have looked at several sites where people have tried this modification. They all make the same mistake in their testing... they test the engine in stock form first, then mill the heads and groove them and test again. I haven't found a single test where they compared  just a milled head to a milled head with the grooves. So how do you tell if it was the grooves that made the improvement or if just milling the head alone was what made the improvement?

Looks like teething pains are included

Batman, you spell like joker.  

I reviewed Mr. Herring's report.  He did a powerfully impressive test.  A lot of work obviously went into that.

I am trying to make a hotrod.  WOT performance is most important to me.  I am willing to put up with poor fuel economy and minor drivability issues in exchange for the best WOT performance I can achieve. Nowhere in the test does Mr. Herring take it WOT.   Best I can tell it never gets past 30%.  Looks to me like his high load data is achieved by throttling the load cell bleed, not the fuel injection system throttle body.  He even states in his summary that torque, power and thermal efficiency were "unchanged at high loads".  I think Mr. Singh's invention has merit for improved fuel efficiency and drivability.

I was confused at first because on almost every data table the stock cylinder head made more horsepower than the grooved head.  Then I figured out that the hydraulic load cell oil temps were higher for the grooved head tests, and as such, registered lower pressures which in turn resulted in lower HP readings.  You can find that nugget of gold in his notes.  I was baffled that he didn't make an effort to use some sort of correction factor to adjust for the hydraulic oil temp.

In his introduction, he states that his test is intended to confirm or disprove the claims listed in US patent 6237579.  I pulled up that patent. It's really cool.  First time I ever tried that.  Best as I can tell, I think what's goin on here is an idea that is intended to improve fuel efficiency & drivability while at the same time lowering emissions.  All good things. I don't think it's intended to make my Savage a hotrod.  The patent description does say the invention should allow higher compression ratio and decrease the tendency to detonate, so I will keep it in mind if the detonation issue turns out to be a real problem.  But I think I would lean toward dishing the inexpensive piston rather than grooving the expensive head, especially since my issue seems to be confined to WOT high rpm operation and this groove thing only seems to affect low & mid range ops.

The US patent office didn't hand Mr. Singh that official number for the heck of it.  There is obviously some merit in the invention.

I've been mildly interested in Singh's work for several years, but I'm not enough of a gearhead to bother.  I was hoping DragBikeMike would take the bait!  

If I had a reason to pull the head off of my bike, then I would probably do it, but it would just be a "seat of the pants test".  Unless my MPG improved significantly because I do keep tabs on that.  

If I remember correctly, he used this mod on some race bikes???  I think that was somewhere on his site.