If anyone is interested, I found that a razor blade scraps all the carbon crap off. Notched pistons take a little more effort. After the razor, blow compressed air to clean as much as you can, then use carb cleaner with a brass brush and a shop rag to wipe off (you have to work in small sections cause the carb cleaner evaporates quickly), that'll get most of the orange/yellow discolorment that was under all the carbon build up. Then spray again with air. The pistons came out amazingly clean.
Over cleaner is not good for aluminum....the bristle disc used for gasket cleaning or a soft wire brush works well also. Tape off all areas you do not want debris in
With the heads on there is a way. Remove spark plugs, add a little GM Top Engine Cleaner (my favorite) or just some carb cleaner into the cylinder. About an ounce. You might want to remove the battery cable to prevent the motor turning over. You will hydrolock the motor if you try to start it after putting the plugs back in. Put sparkplugs back in but just enough to seal them. Let it sit overnight or for at least 6 or so hrs. Remove spark plugs. Disconect the fuel pump or remove the relay. Turn over motor to blow all the carb cleaner out. It will probably come out as a black sludge of disolved carbon, so you might want to put a old towel over the holes so you don't make a mess. You might want to put a little more cleaner in there and cycle that out to give it a rinse. Put plugs back in, and crank over until you hear compression start again. The cleaner will have washed the rings down so it might take a minute or so. Crank for about ten seconds at a time. Once you hear the compression, reconnect the fuel pump or relay and crank it up. It will probably miss and studder like crazy for a few seconds, and there will be tons of smoke. Once it clears out, turn the engine off (do not drive it) and change the oil. It is contanimated with carb cleaner. You might want to change the plugs too. When I worked at a dealer, this is how we cleaned the combustion chambers of engines that were knocking and pinging due to carbon buildup in the cylinders. Worked every time. Looked at one with a boroscope and it really did clean it.... kind of looked like the advertised results of these gas tank additives except this wasn't make believe advertising, this was real. Time consuming as hell, but it gets the job done.