Hot or cold, specific compression pressures don't matter. You're looking for a percentage difference from one cylinder to another. A valve adjustment needs to happen first, as a tight valve will give a false compression reading for a specific cylinder. A flat cam lobe should be pretty obvious if it's severe- - - -watch the rocker arms and/or valves for a difference in the distance they move up and down. It doesn't take much cam lobe wear to cause a visible difference in valve lift, especially since a stovebolt rocker arm moves the valve something like 1.75 times the cam lift distance. A worn exhaust lobe can affect several cylinders since exhaust gas that doesn't make it out of the tailpipe backs up into the intake the next time the intake valve on that cylinder opens. That messes with manifold vacuum and the mixture other cylinders receive. A burned or too-tight intake valve can take out more than one cylinder also, for the same reason- - - -exhaust gas backup into the intake manifold.
Vacuum advance will only affect light throttle cruise and gas mileage- - - - -not low to medium speed and performance. At any throttle opening other than "feather-footing" the gas at highway speed, there will be little or no vacuum advance.
Jerry
