That's cylinders 1 & 7 and they are fed by the same carb, but if that were the cause then cyls 4 & 6 should also be affected. 1 & 7 aren't next to each other in the firing order, so they're unlikely to track across the cap. I would start by interchanging plugs and leads from "good" cylinders to the misfiring ones to see if the misfire moves.