Ignition or Fuel?

The carb was a street strip build by Demon Sizzler. I would have to check on the model, but if I remember right it is a 1972. The vacuum is hooked in to the ported side I believe (front left next to PCV in center) Initial timing is set at 16 with total in at 33 by 2800. I will double check the rpm for total advance. As far as the cam I am using Comp XE 275 with .525 lift and duration at .050 at 231 Int. and 237 Exh. I have 1.6 Crane roller rockers, but for right now still have the factory 1.5 rockers in for the cam break in. I'm using a M1 single plane intake with Eddy heads. MP distributor with chrome box and a MSD Blaster coil.

From the plugs pictures can you determine whether the black fouling is from carbon (fuel) or oil?