i gotta ask , why did you gap below the factory .040 ?? 94-97 was at .035 but again they had a weak ingition (so i been told) i doubt it , they have a damn good ingition system..

 

This was recommended by John Mercedes. He suggested .035-.038 on the 3923's. It's a little tighter then spec to help prevent pinging when your advancing the timing though PCM upgrades. I tried .035 and thought it was a little too tight. So I switched to .038 and have been happy with that.

Really, .040 still works fine for me too. I check my plugs about every 6 months. I clean them, regap them, and reinstall them (or replace as needed). So I do .038 because I find that after running them for 6 months, normal wear on the electrode tip results in a gap of about .040. If I had started at .040, it would be .042 when I pull the plugs at 6 months. That's a little to wide for my taste. If I had an MSD and hotter coil, it mioght be ok, but the stock ignition is not hot enough for a gap that wide in my opinion.

 

hmmmm i need to get into contact with this guy. i took my 3924s out went with 3923 ping is gone , thats with running 87 and at WOT gap at .040