Idk about the timing marks, but I know on my 35ci vanguard it has a advance key and the flywheel is one mark from full + sideevryone tells me that's to much timing but funny thing is the 40 and 44ci inteks that I race are always behind me, I've ran this motor like this for two years now and have never had a problem, I do run vp 110 octane fuel, I've tried moving the timing down and it seemed to run worse, so unless u go with a all out performance build I don't think the ignition timing makes that much difference, my opinion