High gear retard is a real thing and is used by those looking to get the last bit of performance. Was being done years ago by class racers, etc. You can do it electronically or put a switch on the shifter and do it with an MSD retard box, depending on your ignition. Or just set the timing where it gives the results you're looking for - go fast, repeat 60s, not run the engine on "kill".


If the results don't match the theory, change the theory.