When starting my engine cold it runs rough, I mean really rough and belches some blue and grey smoke. After a couple of minutes it warms up and runs as smooth as a baby's butt. Took it to a mechanic, who said that the smoke sounds like seals but that no way could they be leaking enough oil to really foul a plug that bad. He said maybe it is the choke. Sound plausible? It's a carbed 305 with a rebuild about 20,000 miles ago. No big modifications.

 

If it's fouling the plugs bad maybe rings? Did you do a compression test or a leakdown test?

 

Being done now.