Someone on Speedtalk Dyno'ed these and found a repeatable small gain in torque at lower RPM's using A/B testing... From what I read I found the tester to be believable, apparently unbiased and the test rigorous. The guy noted that there was a definite small boost in torque but no other measured gains, on a motor that was not necessarily optimized for the grooves... the compression staid the same, and timing was not altered to take advantage of the (claimed) benefits of the grooves. The same head was altered, with the only change being the grooves and runs were averaged.
All that said, there's no apparent scientifically sound methodology to the grooves. There's no rhyme or reason to the placement, number of grooves, size, depth or orientation.
So perhaps the couple foot pounds was an accident of slightly improved quench action, Maybe all less than perfect quench designs could benefit. But perhaps the same sized and oriented grooves in a different chamber design would cause a couple foot pounds loss...
The truth is that no one out there really wants to spend serious (expensive) dyno time thoroughly exploring the possibilities of grooving quench pads because these grooves (and the people using them) seem at face value to be less than scientific.
In my personal opinion if it does what the "inventor" claims, it is probably a complete fluke of the random probability generator
