car still diseling run on prob

What is your timing set at? I personally would run 91 octane, a 180 stat, and by looking at the heat range on those plugs I would go a step cooler. I run NGK's but anything a step cooler should be ok. I think its a combination of things, not just one specific thing. for sure at least run the higher octane and adjust the timing then reset your idle screw as the plates are probably too far open.