Mike.
What I am seeing is a badly carboned up engine..No idea what the bottom end is like but the valves are not all burned up and split..a good sign..and once you pull the engine and can see what is going on down below you will have a better idea..
That happens when they spend a lot of time idling and slow..low RPM operation..
Rich on the fuel under these conditions..hence the carbon..
IF all the other tune up points ..timing..carb...valve..etc.adjustments are in spec..
Anyway press on..Keep the pix coming..
You are doing fine.
One more thing..DON'T let your "Car Buddies"..talk you into pounding those pistons down "JUst to see if..."...what ever..
Pull the engine.take off the pan..disconnect the connecting rods ..then you can use a wooden block and tap them to break them loose...but don't attempt until disconnecting the connecting rods and rotating the crank to clear the rods..mark your end caps to each connecting rod and the way they are facing before you pull them apart and throw them in a box..
What I used to do was as I was disassembling... I had a big piece of heavy cardboard and I would put slits in the card board and I would position the components on the card board exactly in the direction..number..combination..of all the components as I took them off ..that way I didn't mix up my end caps..rods..valves..pushrods ,main bearing caps etc..and I knew what went where when ever I got the rest of the short block finished...things look a lot better when you know where every thing goes and which way it came out..
