I wouldn't run ported vac to the distributor.... you're probably pulling in too much timing at idle. Non ported vacuum will all the distributor to just sit at it's mechanical setting (base timing) until the vacuum is needed. Vacuum advance is just a fuel economy issue anyway. It pulls in timing when you're cruising - light throttle - and adds some advance when the motor has little load. The minute you get into the throttle - the advance drops out (vacuum drops) and the mechanical advance kicks in. People confuse vacuum advance as a "power" issue all the time... and it's a common mistake.
There are several items that can cause a high CO at idle...
Missing - so fouled plugs - or incorrectly gapped - or a bad plug wire
Rich idle adjustment
Over advanced ignition timing
It can also be caused by a "lean miss" -- to a too lean idle can act like a too rich idle. Go figure - but it's true.
It can also be caused by a vacuum leak.
I would check your plugs - check the gap - really pay attention to your plug wires...
Then I'd be checking for any vacuum leaks
I'd switch the ported vac back to unported and re-set the timing
Adjust the carb idle circuit using a tach - AND a vacuum gauge... you want to adjust this for highest rpms and highest vacuum reading.
Of course a guy could write a book about all these little issues and there cause and affect -- but I'd start with just the simple stuff and see if things improve before throwing a bunch of dough at it and winding up without a cure.
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