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Old 01-05-2012, 06:54 PM
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Originally Posted by 396chevelle
I was wondering if you guys could take a look at these plugs and tell me what you see needs adjusting. I'm confusing myself. There are a couple that are black and the rest are brown like you see in the pic. #3 was dry at the tip, but a little wet on the threads (fuel). All other plugs were pretty much dry. Should I go a step hotter on the plugs. These are a new set of plugs That I put in after I adjusted A/F on the carb for highest vaccum. The only thing I've done different after that was change the module out in my HEI. By the way this is a brand new 496 that I'm still working the bugs out of. I started to get a slight surge when I stop at the light, which is what made me check the plugs. I checked for vac leaks also before I pulled the plugs to see if that was causing the slight surge. The carb is a Holley 4150 850cfm double pumper. Any advice is appreciated! Thanks,
As Cobalt points out the right side looks OK the left is carboned up which could be manifold distribution, excess fuel on one side, engine operating temp too low, this can be a problem with the front two cylinders that see coolant right off the pump so they are cooler than everybody else. A wiped cam lobe and lifter, or simply the plugs that were all rich and dark from early tuning attempts and some just haven't cleaned up yet because they miss or late fire, or a leaking head gasket, a valve leaking oil down a guide, rings not yet sealing up enough. The fuel wet threads can be as much an indicator that the plug is miss-firing as it is seeing a rich mixture.

I'd throw them away, put in a fresh set and run it a while then take a new look and report the results back here. This time keep them in order so you can see if any are on common sides of the intake, or are next to each other, at the front or rear of the engine, etc. This is so we can consider trends if there seem to be any of related or common problems between cylinders.

On second thought I wouldn't throw these plugs out, keep them for reference but don't run 'em again. And don't get them confused with the next set you take out.

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