Changing valve seals using air chuck: If I have air leaks are the heads toast?

[piecesparts]

I agree, try tapping the valves with a hammer a couple of times to get them to seat, if they don't the heads will need to come off. It sounds like you may have driven a lot of city miles and carboned up the valves. However, even with the low miles, this would be an excellent time to tighten up the upper end of the motor and ensure the valves do not give you hell later. The motor is on the stand and you have some time(I hope) Go a step further and be satisfied that you did everything that you could do. BETTER Than having to take it apart after you have installed it in the next vehicle.