[Walt Fricke]

If you don't have air coming out your intake ports, intake valves are probably OK. But this is of no consequence - you have to take those heads off to replace the bent exhaust valves. With the head on the bench it is easy to check valve seal with Windex or soapy water. Combustion chamber up, solution sprayed on valves, squirt air into port. At normal seat pressure, if they seal you won't get bubbles. If there is a leak, it will show up with just a little air pressure - it is not as if it won't leak at low pressure but will at high.

I used some rubber on a piece of aluminum with holes for the intake studs to hold it in place. Put a fitting in the center of it so I could attach a hose. When grinding my valves and seats I'd drop the valve in and blow in the hose while pushing down on the soapy valve heads - if bubbles appeared, back to the valve grinding machine.

I suspect you could just put the nozzle of your air gun in the port and pull the trigger, and that would be enough to create bubbles if there was a defect in the seat with the valve springs installed.

Interesting idea about trying to see if your rings are doing OK, though generally, absent physical damage you can see or measure when all is apart, you aren't apt to have bad rings on some cylinders, and good rings on others.