Rick,
What Don says is right on the money. It doesn't make sense, at first, until you look at it like this: If you have too much head space, you have to lean down on it too much to get it to come alive, because of no torque. When it does come alive, it is set way too lean and smokes the plug. If you get the head clearance down to, oh, I don't know...... Let's say....... Just to pick a number.......... Somewhere around .006" or so.........
You get alot more torque and it will launch better and climb the pipe much easier on a richer mixture. Your plugs last alot longer and you go faster to boot.
I know sometimes it tough following the advice you've asked for, but sometimes you've just gotta trust someone. Do what you've got to do to get the head space down to .006" and see what happens. It's real easy: If you don't like what you get, you can always add shims.
Thanks. Brad.
Titan Racing Components
BlackJack Hydros