Can I assume this is your first valve job? Make sure you are looking at the correct measurement on the feeler guage. Use the millimeter (mm) measurement, not the inch (in) measurement, or you will have a much larger gap than necessary. Some feeler guages will have enough in them to use the wrong one for intake and exhaust...I've seen some smart people accidentally use the wrong guage. :shock:

It won't cause damage, just some REALLY loud valves