Apparently all that work that Billy22Bob did for you on your other thread wasn't good enough? lol. The only one that I've read about that toasted his SC was Tighed1. Perhaps there were others, but Tighed1 was stacked large, and did a fairly long run down the highway from what I remember. What was his max SC RPM? What would have been the safe RPM? Maybe he didn't have fresh jet oil in his SC . His SC fried, but maybe mine or yours could have made that run and survived. The moral of the story is to not run stacked down the freeway for too long of a blast. My point is, that the number you're looking for is somewhat random. When you get into the stacked territory; you play, and you may pay. It's gambling. A few members on here have done their very best at getting the most possible speed out of their 6 at the 1/4 mile, with every mod,running stacked, nitrous injection, etc. I am thankful for the members that did all the inventing, testing and gambling here(has made it very easy for the rest of us), and I applaud their methodical and careful approach to getting there with the proper AFR's, just as you are doing your research here as well. There are SC efficiency charts for the IHI that have been posted on the forum here if you search for them. Long winded here this morning and didn't really answer your question; sorry 'bout that. Good luck with the journey.