[boxhead]

When you did the distributor work did you replace the rotor cap at the same time?
If so maybe there is a fault in the new cap?
You should really look at what things you did that have changed the engine set up, even the smallest things.
The cap may have been moulded poorly and the pickup has moved or was set wrong, causeing the timing on that one cylinder to be out by afew degrees?
I really cant see a carb fault causeing concerns only in cyl#1
If it specific to only one cylinder it is most likely something that works on cylinders sepperately , ie: cylinder specific.
Did you check the plug gaps?
Please keep us informed, this is allways good stuff to learn from.