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Detonation will typically show up as tiny round balls of aluminum on the insulator, deep inside the spark plug body. The black specs in your pictures are probably carbon that has been baked into the insulator.
 

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Looks way to rich and like you're getting oil in the chamber. Can't tell on timing with the picks (likely due to rich/idle condition).
 

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Discussion Starter #4
so little more info. this is a 440 Mopar with Indy 440-EZ-1 heads. no power adder. i know it's rich at idle. my concern is black specs. i'm concerned it could be spark knock. i'm running 110 fuel. timing at 37 deg. planning on putting fresh set plugs in it and do clean shut off reading. i am going to go ahead and knock timing down to 35 deg and see if black specs go away.
thanks.
 

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Is the center electrode rounded off or still sharp?
Hard to tell in the pictures.
What ignition system?
Autolite plugs??
How many runs on them?
 

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Discussion Starter #8
cut plug is autolight AR3911 probably 70 passes and still looks sharp.
uncut (still has threads) around 20 passes and is a NGK R5672A-9 which is suppose to be 1 step colder. still sharp.
MSD gold box
 

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Discussion Starter #9
Update. car slowed down with less timing. Still had small black specs. I did 2 plug runs. Installed plug at head of staging lane and pulled on return road (clean shut off). After making 2 slow hits and turned timing back up where it was before (i had marked). picked up from 6.4498 106.17 to 6.3248 107.62. So i'm thinking not spark knock. ground strap looks strange.
 

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Looks like it needs more timing, not much heat on the plug/strap, darker tip is where it's burning the cad coating off.
What's it look like down in??
Black specks are carbon, unless the center electrode starts rounding the edges off, then that will speckle the porcelain.
 
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