I agree the vacuum advance is basically for fuel mileage at part throttle driving. Check your point gap & the initial timing. You can set the initial timing a little higher than specks as the gas we get know has more octane then back when these were new. You didn't say what engine you are running. Does the carb you put on have the same dia. throat or larger then the original?
If it is smaller it will reduce the power.
I take it this is a Stovebolt 6 engine. You can tell if the vacuum advance is working by watching it as you accelerate the engine. If you open the throttle a little the dist should turn a little. If the engine bogs when you accelerate after it is warmed up, the carb may be a little lean. If it blows black smoke or leaves black soot on the inside of the spark plugs it is running too rich.
George
