Does it have extra valve clearance on the two cylinders that are low?
Do you hear more lifter "click" then before?
Seats, guides, and valves do not go bad from setting.
Do they stick shut, yes
Can you bend a pushrod, very easily
Will it still run, possibly,
Can they stick open, sure can,
Any of the above can happen from setting, but you should hear more noise then usual.
Clean the stems as suggested above or add some internal engine cleaner to the oil and let it idle for awhile. Recheck compression once up to temperature after the oil has had some time to work
Joe
