My coworker and mentor on all things engine tested the 505BC and the MSD 6 with a paper tape running through a spark. From those burns created he was convinced the autotronics could be used with large spark plug gaps (.045 - .060). Now as far as I can recall, these were open air tests but everything was compared the same way. This is the same guy, also named John, that ran in Stock classes that I mentioned before. He's the guy that told me never remove the big secondary spring from the distributor, because he had learned the hard way that in the electronic distributor it was neccessary.