Grady thank you very much again for your detailed technical answer. Iīm sure one of your forefathers was German..
The valves are the original ATEīs . Iīm sure that i did not measure it correctly. That was just roughly for the picture.
The headīs were overhauled by our local engine-shop and i trust them very well, because they do some cars for the 1000km race on the Nuerburgring. When they measured out my JE-pistons they couldnīt hold on to tell me that Porsche-driving is expensive and iīd better go and buy some good "Mahleīs" instead of this "Walmart"-pistons
The carbon marks are caused by a mounting error caused by me. I forgot to tight up some screws with the correct torque.
BTW: Did you ever saw how the valve-piston clearance is measured in Waynes book ?