Has anyone seen this on a plug? If so what is causing it? Engine is a 355 with 3,000 miles and is running rich. It makes what I think it’s a knock sound coming through the exhaust. All the plugs on the right side of the engine look like this however the left side plugs look normal.
She run’s pretty damn well, I rebuilt the engine around 300 miles ago. She’s got a stock bottom end, .30 bore, heads from a 71 camero, new edlebrock intake, 1103 summit cam, headers and a street fire msd distributor
Oddly enough this tach (which I bought on Amazon) advertises it works on 4-6-8 cylinders engines however it doesn’t have any switch to change between them