More than a little rich!! Buick plugs look really lean even when you are running 12 to 13 to one AFR's. I think that is why Buicks have a reputation for running good when they are lean. Your plugs look lean but if you run a meter you will find that you are not even in the 13's.
Here a link to sparkplug reading I use.http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html If you get it narrowed down with a near right mixture and proper heat range this link is good but not real world (not mine anyway). http://members.uia.net/pkelley2/sparkplugreading.html Ray
I find Ray's second link very good. The first link is totally worthless for me and I suspect most of us. Part of the reason is that we are using unleaded fuel and it does not show the same "color" that we used to look for when running leaded gas.
mine look exactly like #14 with a 670 holley street avenger on my olds 403. Makes me feel reassured about my tuning habits. Thanks for the link! Doug:3gears: