You may have seen my recent post regarding a head gasket issue on an '89 Cressida. The gasket wasn't outright broken but the machine said it showed signs of cross port intrusion. After cleaning the old gasket residue off this block preparing to put the surfaced head on I noticed some marks about the width of a pencil line between a few of the cylinders.
They're more than just discoloration, I can just feel them with my finger. Anything to be concerned about? Is this evidence of firing between cylincders or something else?