Spark plugs - feedback on color

roadrace2

Veteran Member
Jan 13, 2000
1,860
Earth......?
took these out of my GMC pickup - with a crate 350 (stock, with performer edelbrock intake and Holley 600 cfm carb) - had 8000 miles on them.

What's your opinion? Seems like a little contaminates in the fuel system - (red color = rust?) - maybe running lean too?

upload_2021-10-16_14-19-40.jpeg
 

jeff swisher

Veteran Member
Apr 26, 2018
1,934
Yukon Oklahoma
From this view they do not look too bad the red is from deposits from the additives they put in fuel.

I pulled some from my 302" Ford that I had set up pretty lean and those plugs looked like you just pulled them from the box after 20,000 miles.
I was running a ported 2 barrel iron intake and a very rough intake runners all the way to the valve seat.

I think your plugs look fine.
You can try and lean it a bit and see what happens with the MPG if you do not see an increase put it back where it was.
 

roadrace2

Veteran Member
Jan 13, 2000
1,860
Earth......?
Cool! Thanks Jeff! - Got the timing right, focusing on the fuel now - will lean it out a bit. Fuel economy is important as this is a daily driver.
 




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