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What do you think about these plugs? I pulled them out of my 5.3 with a Whipple blower--14# max. They have about 15 short WOT runs with a short drive each way. I am using octane booster, for about 6 of the runs. Cranks and idles OK, idle is tad rich but the O2 sensors take care of that. WOT is about 10% rich on these runs. I have a new set of plugs coming , WOT is only about 3% rich now. The first two threads are a little wet from fuel---210 injectors.
I cut 4 more and there was a fuel ring visible, but not like a pencil line. I have been tuning a new engine and it has been running rich for several passes, plus idle and drive around time. I guess that's why the ring is not straight. I will check the new plugs after one run.
Last edited by dw456post; Apr 27, 2024 at 03:57 PM.
Here is the new plug after two runs. Fuel band is visible and shows rich---wideband showed rich also. Fixed that.
Timing looks good on the ground strap.
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Spark plug reading 
