Bad news. The engine went bust. Three out of four cylinders lost compression, and one of the three has a cracked piston, zero compression.
The owner went driving on a highway at 170 Km/h (105 MPH) and the engine was creaming at 4500 RPM for two hours, and with my excessively aggressive timing the engine couldn't take it anymore.
I was relying on my ears to hear knock when I was tuning, and didn't hear any even at 3 degrees timing advance at WOT, and even more at 4000 RPM, so it is my fault. Even though the car was performing amazingly when it worked.
The guy gave up and I'm removing the supercharger for him. Why do people give up so easily?! I told him I found the problem
Tomorrow will drop in a second hand engine, and he will be on his way.
Now I'll have to look for a new customer for the supercharger.