Pulled Plugs - What the Heck Am I Seeing???
 

418W - 750 DP Holley - Performer Intake - MSD 6AL Ignition - MSD Pro Billet Distributor - 11,000 total miles

After a few recent miles in the Cobra (1000+) I pulled the spark plugs to check them out and this is what I found:

#'s 5 thru 8 were tan - chocolate
#'s 1 and 4 were tan - chocolate
# 2 looked like it was brand new (I mean brand spanking new)
# 3 looked a little used but still white and nice and clean

When I pulled the last set of plugs they all looked very much the same with the dark tan - chocolate color!!

The engine does not seem to be misfiring and still makes great power. I think I am having a fuel delivery issue but where do I start to look?

Thanks in advance for your advice!

Terry, the colors noted on plugs 1, 4, 5, 6, 7, and 8 sounds correct or close to it without seeing any pictures.

Are you sure #2 is firing? If the plug is that clean it sounds like there is not any combustion taking place in that cylinder, I assume you know how to check for spark on that lead, it may also be an issue with valve timing/closure/setting.

Your description of number three sounds like it could be a fuel delivery problem which often (not always) indicates a vacuum leak in the intake at or near that cylinder. what kind of driving are you doing? Think about an intake manifold leak check or possibly a pinched/blown head gasket (fluids are clean?), after you have made sure there is spark and proper valve action/closing/adjustment, making sure you have good compression on the cylinders in question without any leak down or low readings.
Its a start.

What type of plugs? Please tell me they are not champion. I agree that it sounds like you may not be getting enough fuel but I would start with the basics and check the plugs then the valve adjustments although I would think it would be running a little rougher if you were not getting fuel.

Mpanten - The plugs are Autolite and I do not remember the part number!!
Hydraulic Roller Cam and the valvetrain does not sound noisy at all!!

Warren - Great link, thanks!!
The majority of the plugs look like # 14 except for # 3 which looks like #23 on the chart and #2 which looks brand new!!

The chocolate brown color indicates that all is well. Black or oily plugs
...the car is running too rich, or there are seal issues.
White plugs would indicate to me that you may have a small coolant leak
in the intake gasket on that cylinder, or cylinders. The coolant or water, as it
slowly enters the cylinder will turn to steam vapor from the heat of combustion. It will "Steam clean" the plug, and make it appear "New".
The car may not miss, or run badly because the leak is too small to cause the
plug to foul, or interupt the firing of the plug. If the leak gets bad enough,
the engine may miss, or you can detect as small amount of steam vapor
coming out the exhaust. The coolant level may not appear to drop because the leak may be very small. I am not a big fan of putting stop leak in a system, but I have seen it work on small leaks such as this. I have been in the radiator business my entire life, and only know of one such stop leak
product that generally works without causing other problems.
Bar's leaks.... It is made of pellets made from ground Ginger root, and ground
almond shells. The almond shell particles remain solid, and keep the ginger in suspension for a while, and then they dissolve. The Ginger root stops the leak.
It finds it's way to the leak and enters the area. It enters a crack and begins to swell up on the way out when exposed to air or heat and air. The more of it that enters the crack...the more it builds up..and then the seal will be
made.It coagulates in the crack like a clot. The only downfall to the product that will cause it to fail is vibration. Heavy vibration. Stop leak[bar's] can be a quick fix, and can last. Sometimes better than taking the intake off, and going through that labor. The leak will be in the INTAKE GASKET, and not the
head gasket. The water or coolant will be entering the cylinder from the intake port or ports.
freekintoad