This is the hydrogen injection paper, and I think I remembered wrong and they used a Duke. Titled "Ultralean combustion in General Aviation Piston Engines" dated 1979!!
http://ntrs.nasa.gov/archive/nasa/ca...9800013943.pdf
There was also another interesting paper on cooling air inlet design by Miley Owens & Lawrence
There is also a paper by Gerald Slusher of NASA which looks at exhaust gas temperatures at various locations, exhaust component temperatures and engine vibration levels. I got some interesting points about the variation of exhaust gas temperature, but I needs a serious read.
There is also some papers from Lycoming & Continental engineers that aren't available on line that I have requested.