You're rich at idle, cruise looks close. Can't see WOT, it is way down inside the plug, sometimes you have to cut the plugs to get at it. Heat range is ok. May be using a little oil, check your PCV. The rust at the base of your plugs could be causing a bad connection, try loosening and tightening them couple times to make sure they have a good ground connection. May be time for new plugs.
Attachment 72423
Doesn't look like your distributor has adjustable limit stops, there are some downloadable articles on line about how to modify your distributor.