vacuum advance

RedFish said
Are you sure it was originally manifold vacuum supplied. Most were venturi vacuum supplied.
When it comes to vacuum advance, The more I read the more confused I get.
Can manifold vacuum source be better than just disconnected ? Does manifold vacuum even drop enough to cause the advance servo to respond ?
Can I assume what works best for performance also reduces mpg ? I would forfiet a little mpg for better throttle responce and overall performance from a totally stock 2 brl. engine.
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All I know about the original vacuum source is from our formula s 273. It has the stock carb and manifold on it.There is only 1 vac fitting on the carb and it has a lot of suction when the engine is at idle.
It is only running a single point dist, my dual point dies when I apply any advance from the vac adv. I have to leave the vac advance disconnected if I want to run the dual point on the s car.