SBC, Vortec Heads, RPM Air-Gap, Edelbrock #1806, MSD Ready-To Run with Autolite 103's. Plugs 2, 4 & 6 are all a bit richer looking in person, with #6 being the richest. Plugs 1, 3, 5 & 7 look the same as plugs 2 & 4. Plug #8, vacuum leak or what? Thanks for any insight.
Two and four look about like what I would want to see on today's gas. Number 8 sure does look like it was running lean on that cylinder. The vacuum port is in the #8 runner. I'd be checking down stream from it if you have a vacuum line connected to it as there may be something else causing a vacuum leak like a diaphragm in a heater or defroster control.
This will help you out. It has virtually anything you need to know about sparkplugs... http://dirtbike.off-road.com/dirtbike/article/articleDetail.jsp?id=332655
I am only running two vacuum lines. One goes to the vacuum advance from the front of carb (full-time vacuum port), and the other goes to the auto-trans modulator from the vacuum fitting on the rear of the carb. The intake runner vacuum port is plugged.
Bad plug wire on #8.?make sure there is no ideling time before reading plugs.that is cut ignition under power.
Forgot to mention the pix are from the idle circuit. Wouldn't a bad plug wire leave carbon build-up or residue 'cause it wasn't burning off?
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