Setting the Dwell is kinda like fine adjusting the Points while the Vehicle is Running:Set Points to to .021 Dwell = 24 - 29 degrees
1) Connect the dwell meter as per its manufacturer's instructions: Generally one of two leads is connected to the positive terminal of the battery and the other lead to the negative terminal of the coil.2) Start the engine and read the dwell angle (making sure meter is set on 8 cylinder).3) Adjusting dwell is somewhat of a trial and error process. If dwell angle is too high (points closed for too many degree of rotation), you will have to carefully reset your points to a slightly larger gap. If the dwell angle is too low, the points will need to be set slightly closer. Adjust the gap .002" or .003" at a time for best control.4) Restart the engine and re-measure dwell angle. Repeat as above until dwell angle is correct.
Vacuum is usually checked at a main Port at the Intake Manifold.Intake vacuum exists in the intake manifold as a result of the pumping action of the engine's pistons, open & closing of valves and the restriction created by the throttle valve.A Tune Up & Timing can Increase Vacuum to a certain point, but Vacuum can only be increased by increasing Compression & Valve Adjustment