Ya the pic is hard to tell sorry. I know it's not valve seal, I just had these heads completely gone through 2 months ago and maybe have 50 miles on em. At first I was thinking piston ring? But it couldn't be because I had great compression, and I never ever blew smoke. I'm just going to assume it's carbon buildup, since I can crush it with a screwdriver lol. Still waiting for other little parts! I was thinking of this cam for the 360. Whats everyone think? http://www.summitracing.com/parts/cca-20-600-4/overview/