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I believe your vac hose connection change was correct. The 14 seems a bit low. From all the diagrams I've seen as to where the distributor vac advance hose is connected, it's the largest port of the two or three ports within the throttle body. On my 82 8V it's the first one on the left side as you face the front. If all you did was swap out the valve cover breather tube, you're fine. You may also want to check the integrity of the port holes on your throttle body. They may need cleaning (use carb cleaner). The following is some vacuum theory as it applies to adjusting the timing and posted on this very site in a FAQ.
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Under light engine load conditions, there is a high vacuum in the intake manifold caused by the restriction of the partially closed throttle valve.
Consequently, there is a smaller amount of air/fuel mixture delivered to the combustion chamber. Because of the lower ratio of fuel to air, the mixture will not burn as rapidly; therefore, ignition must take place early in the cycle. To provide additional spark advance control based on intake manifold pressures, a vacuum advance mechanism is incorporated in the distributor. It contains a spring-loaded diaphragm which rotates the breaker plate assembly in the distributor. The vacuum diaphragm is connected to the intake manifold through one of the throttle port nipples. When the engine is at idle, intake manifold vacuum is high and the ignition timing is advanced. When the engine is accelerated, intake manifold vacuum drops, retarding the ignition timing of spark plug firing. While performing vacuum testing, you should make sure that you are not contributing to any vacuum leaks or disrupting any sensor performance. With the engine idling, the following are general indicators of engine performance:
Good Operations - An engine in good operating condition should have a steady vacuum at about 16" to 22"Hg. Opening and closing the throttle quickly will cause the needle to drop to 2 and then come back to about 25.
posted by 152.163.20...
, Mon, 1 Jul 2002 23:14:42
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