According the specifications, the only differences are the magneto bearing diameter (bushing) for H30 and 82 and earlier H35 are .9985 and .8735 respectively. The other spec that is different is the timing, which is .035 and .065 inches BTDC respectively. I've pondered this before when swapping parts around. Maybe [MENTION=5969]markus[/MENTION] can illuminate some more differences, or offer insight on why the timing is different. Given that the mag bushing is different, I'd wager the 30 and 35 use a different flywheel as well.