I know this sounds like a commercial coming from me but the Team Orion plugs are just the best thing out there. The most durable plug around, and with the heat range to satisfy anyone. We normally run the #5.

Somebody was asking about unstable running with 5 gallons through the engine. First, 5 gallons ain't bad. I would expect between 7 and 9 if you REALLY take good care of it, but even if you suck a tiny bit of dirt during that 5 gallons, it's not going much longer than 5. Also, it's tough to trouble shoot this stuff on the internet. A guy could complain and his stuff is dirty, bad clutch bearings, bad clutch set-up (mixing manuf. parts), bad tune, dirty filter, bad fuel, etc. I'm not saying that's anyone on here, but I've seen that where it's not maintained and then people wonder why it doesn't run right. With good fuel and top maintenance it should purr even when there's not much pinch. Then you slowly have to start turning the idle up as it gets old, but it will SCREAM on the straight.

as an aside.. 98% of the people that ask me to tune their engine have the top end needle too lean, the bottom too fat, and the idle too high.. no kidding.. It's getting where I can almost make the adjustments before starting it. It's normally a half turn too lean on top, a turn too fat on bottom, and the idle needs to be turned down about a half turn.. roughly