I do know of one cleaner that can probably get rid of anything that is dirty in a motor. I've seen this stuff eat away carbon build up. Its called "GM Top Engine Cleaner". I know this is a GM product but it can eat anything away. All you have to doo is Put this stuff into your motor and let it sit for about 24hrs. After that period start the car up and notice all the black smoke, All this is just the crud in your engine. It will clear up after a few minutes.
Solid Black 1987 T-bird 5.0