Ok in my pics are three pics of two plugs. All you that know what to look for give me your opinion of which plug (left or right) looks like it is the best. Thanks

 

The right one, looks a tad more rich which will give your engine some longevity.

 

One on the right looks better. Left one may be fine as well, but I like the extra assurance of running a little rich. [img]i/expressions/face-icon-small-wink.gif[/img]

 

Right looks right....

 

I forgot to mention that the left was mixed C12 with 91 octane and the right is straight 91.

 

I agree....the right one looks better. The left one has been operating in a lean condition. Personally, I like my plug a shade darker than the right one.

 

me too.......both look a little leaner than I would feel safe with........

 

I thought that mixing race fuel with regular ( 1 gal C12 to 4 gal 91) would help the lean condition. But the plug that looks better is on straight 91.

 

The plug on the left doesn't look too bad, you can't go by the color of the porcelain, only the color of the base ring and/or down inside the plug where the porcelain meets the metal plug body. Race gas makes spark plugs hard to read, why are you mixing fuel? Do you have internal engine mods?

 

Yes 11: 1 and stage 1 cam with port and polish. I was trying it because some had said that running just 91 octane maybe not the best to use, so I tried mixed.