The carbon on the intake valves can only come from fuel or oil so if the valve seals are not damaged then it would be due to running rich.

is the stuff on the back of the valves gooey/gummy or powdery/crunchy? just seems like oil from the pics vs soot... are all the valves equally cruddy or is it localized? if all the same it might suggest the oil was coming in through the intake manifold (pcv) vs localized leaning towards individual valve seals.

Look at the head pic of the combustion chambers. The last three cylinders I had most of the issue, but #2 fouled on me also.You can see the difference looking at the valves from a distance. The pistons had a sheen to the top of them besides also having a carbon layer-the shinier ones were 4,5,6.

There were moments I had this motor running rich, but with a wideband I knew most of it's life--until lately--it ran well. I didn 't have a perpetual problem with this motor running rich or the O2 sensor would have showed that. I had some carb issues , but I always knew I had a problem right away because of the o2 and looking at my plugs.

Maybe a combination of issues piling up on each other. I knew I had an issue with rockers-which effected valves, which needed to be addressed. I didn't expect to see this much build up.

I didn't really poke at the crud on the valves and i haven't seen them out of the head. The head is at the machine shop now.

I will say the HG showed had this crud on the fire ring edge and it wasn't hard, more oil like mixed with carbon.

Well the block and pistons are at the machinist. A cursory inspection by him and he said I had nothing to worry about. He agreed to measure everything out and thought a good hone and new rings and I would be good to go. I pulled the crank out of my original motor and going to replace the crank in this motor in order to eliminate the speedi sleeve on the rear seal. I guess you would say I am starting over again from the beginning. This time I will do all the assembly work. It's time for me to learn how to do this and I feel pretty confident I can do it.

I haven't heard from Schneider on the progress of my cam.

I miss driving my Z

So here are some pics of the cylinder bores. Also pics of my Chevy Sonic pick-up truckLOL