Hi Jim:
This was something we tested several years ago and didn't keep the dyno data after a series of back-to-back tests using the same engines. It was simply done to quantify some observations about windage in these engines. This was part of some extensive R&D using vacuum pumps and different ring configurations,...
For example, I think its a great waste of time to do a 2.0S that will not see much 7300+ usage compared to a 3.6 being run to 7K+. One must remember that Porsche used the same case dimensions in ALL of these engines and the volume of air moving around inside the case varies with displacement. Big motors see greater benefits than smaller motors do but all race engines (Al) should be done if one anticipates RPM operations well above 7K.