I remember some of the older tuner garbage. So and so could set the points, timing, and idle mixture by ear and when he was done you could stand a nickel on edge on the top of the air cleaner!!!!

When I get one of the real "pounders" put together, and set on front and mid engine plates with a urethene mount at the frame the engine usually thumps so hard a 3/8" drive socket won't stay on top of the air cleaner at idle, and when ya blip the throttle it's tough to keep your hand there!!!!!

Anyway, I set everything with my timing light with advance knob on the back, a tachometer, and an exhaust analyzer. Is vacuum even any kind of tuning device on the high performance stuff? Not sure I even have a vacuum gauge anymore. I just set my initial timing so it will start, sometimes with an ignition cut off switch to let it get cranking before the spark hits.... Then tune in my vacuum advance (if used), set the rate and point of the mechanical advance, then get the total timing where I want it. Only thing left after that is a couple pulls on the chassis dyno and a bit of tweaking on jets and timing.... Without power brakes (I much prefer twin master cylinders and a proportioning valve) where or what am I missing that a vacuum measurement would be an issue?????