Timing or Carburator problems

[javcamac]

Hi to all,
I have a 360 engine that I recently change the spark plug and notice that some of them were burned dark/black instead of clear/brown. To be exact there is two spark plug from one side and two from the other side in that conditions.
My question is. Is a out of timing problems or is the carb problems. Also I have a HEI ignition installed.
Thanks for your help...jc

 

[Jester32]

Usually black is carbon build up from oil. Rings or valve seals or guides.

 

[javcamac]

I thoughts that timing maybe are the problem because only spark plugs number 1 & 3 and 2 & 6 were the problem. The other spark plugs were fine.
Thanks for your answer and help.

 

[Jester32]

Timing will usually show on plugs if it's way out and it detonates. Then it will be damaged or melted. Usually would be apparent on all plugs to if it's timing.