My run out last week to the Distinguished Gentleman's ride finally got me to the 3000 mile service.
I run the clearances on my all iron engine at 010 and 014 thou. One was still at size and the other three were tight, by maybe a couple of thou. I probably looked at these last around 750 miles ago. Is that normal movement or might I be experiencing a little valve seat regression?
I mostly run high octane and always with Castrol valve master lead additive.