[Jac Mac]

Jack,

Ray has a supply of upmarket vacuum line blockoff apparatus that he could sell you if you need one!! I dont want to stand on your carb man's toes, but I cant see a problem with plugging the vac until you sort out the mech advance curve. If your duraspark is the one Im familiar with shortening up the mech adv amount is not a major and can be done on the car with the aid of a timing light and helper to call out the rpm for you, if your familiar with what needs to be done.

When did you get 12mpg, with the old carb? or this new one?

Jac Mac