Trust listed CFMs and PSI on Air Compessors?

I found an used Craftsman 5hp 220v, 30 gal with it listed on the side "12 scfm at 40 psi and 10 scfm at 90 psi"

I am a bit skeptical for one, its a quite a bit cheaper than anything close to that, and two it is a 30 year old craftsman. To be fair it says Sanborn on the label. Model ML109CL300-20.

Worth the $225? Can I spray paint with it? Run an impact or die grinder? If duty cycles are a worry, I like taking breaks.

I've got a very old craftsman.....30 gallon, 220, dual cylinder, direct drive, oil less, noisy....not sure the model and airflow off hand.  I got mine as a free hand me down. If this one is the same as mine, knowing what I know about it now, I wouldn't pay 225 for it.  Mine had tons of water and rust in it due to neglect. I got it all cleaned out.......but being so old, im constantly wondering  just how safe that tank still is. Every time it's running up to max psi, i tend to try to be a good distance away from it. 

30 gallons is a fair capacity.....It will run a impact no problem. Die grinder will work fairly well, but if you're really using it, expect  some cycling breaks.  I've run a media blaster with mine. Eventually the entire tank gets hot and you start getting lots of water through the hose which obviously is no good for media.  Painting I would think would be plenty capable, though you'll need proper filtering/water separator and a separate regulator at the gun. 

My compressor doesn't cycle on till a bit under 80psi, then runs all the way up to 125 before shutting off.  It's a bit irritating with impact guns when you need the power but the tank is on the lower end of the swing, forcing you to essentially vent the tank to get the compressor to cycle. 

This one says it is an oil type compressor.

I think you could trust the ratings unless the motor looks really out of place. What I would be concerned with is the tank itself being full of rust. 

Shake it if you can, it'll sounds like gravel if it's bad, shouldn't make much noise if it's good.

The old ones are probably more honest than the new ones.

Mine is a 1971 Quincy. 18.6 cm @ 175 psi. When turning 900 RPM FTMFW.

With that compressor being so old there's a decent chance that at some point it could actually run at those rates (and probably still gets close to them). If you are cross shopping against new they often rate the CFM at the inlet rather than the outlet. So a compressor will be pulling in the rated CFM but only delivering a fraction of that at the tool at pressure.

I had a single stage, two cylinder, 2 hp Craftsman compressor like the one below.  I painted something like 15 cars and trucks with it.  The compressor would run out of air if using a DA or air board for a prolonged period.  Nearly as I can figure out, it did 7.8 CFM @ 40 PSI and 6.1 CFM @ 90 PSI and was from the mid-1960s.

Don't think I would pay $225 for it - I just gave mine to my daughter's boyfriend.

There was a lawsuit a bit ago against Campbell hausfeild where they basically put spurious locked motor peak horsepower ratings on their compressors. I've always not looked at hp but scfm to judge a compressor.  I think the thing to look for is scfm at psi.  Hp is marketing puffery.