That's the normal way to clean intake ports. Don't be afraid. Blowing them out would be a better idea than vacuum, unless your vacuum is spark-proof...The valves are all closed except for one valve on cylinder 3. I vacuumed out some of them, but im worried about some of that sludge dropping down on top of the valves. Its it okay it fill it with some marvel mystery oil or something and scrub it out with a brush? Then blow out with the air compressor, then vaccum?
Yep. Clean her up. Then Run some seafoam through the fuel to see if you can get the rest of it out.
Can you take it completely off? Then you can really clean up good. Put it back on nice and clean...Can use brushed with some carb cleaner to see if it can break up and get super clean.
Edit: I was referring to the intake manifold you took off can clean.Carb cleaner would clean that right up as well on the intake head ports..