Vacuum test for valves?

[specialk2003]

Has anyone ever heard of doing a vacuum test for the valve seat? I just had a head milled and the guy said he vacuum tested my valves and they were low. He had a hand-held vacuum pump that was attached to the air line and he pressed it up against the exhaust port and the reading were between about 10-13"hg. He told me that normal is above 18".

Has anyone ever heard of this before?

[Tantwoforty]

that can tell you if your valve clearance is off yeah, was it like a plunger lookin thing that covered the valve? and then he pumped it up and saw how much pressure it would hold?

[specialk2003]

yeah, only it wasn't actually a pump, it was hooked up to an airline so you didn't have to pump it.