350 Ram Jet Engine question

We put a Chevy 350 Ram Jet crate engine in our 52 Chevy PU about a year ago. Overall, the engine has been great except that it smokes (black not blue) out the driver's side exhaust pipe. I've pulled the plugs on that side of the engine (1,3,5,7) and have noticed a black "soot" looking residue.
Some of the local advice I've received says it could be too much fuel and a possible injector problem. I'm planning on swapping injectors between both sides of the intake manifold to see if this helps.
Has anyone experienced this type of problem on a fuel injected 350 before? Any advice or other ideas for a solution would be appreciated!