Quote Originally Posted by EagleMark
Next time your at the track, make a run and if breaking up at high RPM? Change plugs! Now take a run.

Don't feel bad. I got done tuning a freinds Big Block Mopar. Put the final chip in for a test drive and the driveshaft broke about half way through first gear... OK, I'm done!
Mark, you're obviously not understanding what I'm saying.

My timing tables are extremely conservative, compared to what other people are running in similar combinations. I'm 8 to 10 degrees less than what they are running in the top end. So much so that my AFRs go real rich. Last night I started adding timing and my AFRs started dropping at those same points. It's not a spark plug issue, it's a spark timing issue.