318 Running Rough / Backfiring

Rich... yes, but the cause of being rich? it may not be the carburetor. I would bet it would be poor performing spark, thus the reason for inconsistent showing on the plugs. Had the same thing with my 318 a few months back, and found my ECU wasn't getting consistent/poor ground. Car smelled rich when idling. Now it's doing great.

Just a thought......