All Plugs Fouling on Right Bank

Help! All right bank plugs (2,4,6,8) are fuel fouling on a newly built 273 Commando Formula S, have a black soot. Left side plugs are clean. Besides running in the driveway, I've only run the car up and down the street a few times. It idles rough.
Solid lifter cam is just a bump bigger than stock and degrees during the build. I'm using the stock manifold and AFB. Exhaust manifolds are stock, and the heat riser is opening as it warms up. Stock dual point dizzy. Initial 14*, 35* with vacuum.
The heads were resurfaced and when I assembled the engine, I found the intake wouldn't quite fit. Took it back to the machine shop and had the manifold surfaces shaved a bit and I was able to bolt up the manifold. I was thinking maybe the manifold isn't sealing against the right head. I ran the engine about 1000 rpm and sprayed brake clean where the manifold and head bolt together, and around the carb, but there was no change in the idle.
I'm looking for ideas... Thanks for all who reply.