Missing, for sure I can feel each header tube and the front two are cold and I have spark.

Checked headers, all OK.

Checked all valves and compression is good.

Wires are correct and swapped with other good motor.

Not much more to check Maybe the front carb is screwed up causing those cyls to either run lean or flood? seems to be a very odd set of symtoms. keep us posted

Float needs adjusted, carbs over flowing, just a thought.

Typically when a vacuum gauge is erratic, there is a problem in the valvetrain. Either a rocker is out of adjustment, a lifter has collapsed, pushrod out of the rocker, etc. Pull the valve covers and start looking. I would bet that you will find your problem.
Eddie

Swapped carbs with good motor, no change

Swapped carb with good motor, no change.

Compression is good and I checked and adjusted the valves.

Remember, it starts out with a good idle and go's bad.

I noticed a tiny drop of water on the spark plug when I pulled it out so I pulled the header and there was small amounts of water in each pipe (tea spoon). I'm thinking it was reverting water when the idle dropped down lower. So I swapped headers with the good motor and same bad idle. Could it be that there is a crack or blown head gasket that when the cylinder warms up the crack or leak opens and lets moisture in and shuts down the spark plug.