Forget about plug chops when your gasoline contains ethanol... It's not completely obvious yet what's happening, but I've seen some weird results, and I'm not the only one...
Furthermore, doing a plug chop is only useful when you do it exactly right - most people forget things like warming up the engine with an old plug and changing it for the new one only for the test run....
@matthew : If I were you, I would stick with the standard setup of an 82 main jet, standard airbox with a clean filter, all clamps and hoses properly fixed the way they should be, and everything checked for cracks and other leaks - doing a plug chop shouldn't be necessary at all then... If it still won't run correctly that way, there's something else going on...
Edit : this is almost the same as skippy said... I think it's past bedtime for me