Gentlemen, I need to pick your brains,

I got a 261, that was rebuild (the whole 9 yards) and driven about 500 mls without any problems, but than just sitting there for 10 years.
Now i fired her up again, and found a ton of gas in the oil.

Looks like I don't get fire on cylinder 2 and 3.
Of course I checked the low hanging fruits.
Distributor, wires, plugs - also tested with glas plug, I definitely get spark, just no fire in the hole - compression is fine (still have to do a leak down test though).
Vacuum gauge shows a vibrating needle just under the green zone, which is valve guides (as far as I know) but since they are pretty much new I doubt it.

Valve train looks working fine, at least while looking at it, while running her without a valve cover - no valves seem to be stuck.
Got an electric gas pump, so that rules out a leaky pump problem.

Got a dual exhaust - I observed gas droplets coming out of the tail pipe of the first bank.
So the only thing I can think of is damaged rings.

Is it possible that they got bad, just by sittig there for 10 years?

Any ideas?

Thanks, Frank