[araine901]

I have run Chevron 91 (used to be 92) since one of the Engine builders at Cosworth did my heads and told me to run that as a first choice. That was back when that was the only grade of Chevron that had Techron in it. Last time I had the heads off the CC's looked like they were painted with a light coat of ultra flat black paint. No build up or clumps of crud.