Groove Photos from 2005 http://somender-singh.com/content/view/68/49/   
and 2006 http://somender-singh.com/content/view/119/49/

Wow, I was thinking circular cuts or spirals, but these are just a simple slot hacksawed (Ok better than a hacksaw) in to a beefy part of the head.   I'd know about this fellow a couple years ago, but wondered if it would ever pan out. He's got some racers running it now, maybe it will go somewhere.

I was wondering about using some of the Ceramic Coating services that coat engine headers and high heat parts. Would a ceramic piston crown provide better heat retention for better burning of WVO ?  Would it be worthwhile to coat the inner head ?

I'd had the headers on my truck done when I had them installed, and the pipes still look good, not shiny but after 150,000 miles, not a speck of rust (but they were SS).

This stuff is some sort of ceramic powder, that's applied, and then high heat baked to fuse it to the metal.

http://www.engineceramics.com/
http://www.jet-hot.com/
http://www.performancecoatings.com/