Thanks for the replys.
The problem starts with the higher summer temperatures. 91F-94F.
Gasoline 98 OCT (us 93).
Idle 840-880 RPM. Vacum idle 10-11.
Initial timing 12°, total 33°. Blue bushing, 2 blue springs. Mech advance.
Idle AFR 13-14. Driving AFR 13.5-14. LM2 in the car.
Compression 10.0-10.5. Highest is cyl. nr. 6 with -11.0.Water 190F.
Oil 180F.
Cam is CompCam 31-760-8 / 288R
Starting the engine is no problem. No chock. No noise until engine heatet up.
The noise appers irregular on the driver side valve bank next to the distributer and the cyl. nr. 6 and 5. You can hear the nois aswel as little high clear note in the sidepipe.
Rico