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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vac. advance should help mpg either way its hooked up. either way it drops out when your on the floor boards with the throttle and you revert to mechanical advance. the vac advance will help mpg at cruising speeds and low speed driving. you need less throttle to get the car moving with more advance. with manifold vac used you'll have all that advance even at idle. all that advance will cause the idle to rise. so you turn the idle down to where ya like it. that = less gas being used. then when pulling away from a stop the more timing makes it possible to use less throttle to get the car going.

going ported vac, will do the same thing just not at idle and pulling away from a stop. cruising though it will allow you to use less throttle to pick up speed.