Vacuum reading question

[Turbo6Smackdown]

I was studying vacuum readings, and stumbled upon two different diagnoses. (lower than normal with a very fast 3-4 inch variation) I have Holley saying it may indicate an ignition problem, and that wouldn't surprise me whatsoever as I think I'm hearing a very slight miss at idle. Though Mityvac's directions claim worn valve guides. Anyone here have similar problems in the past? The link to both sites that I got my information from are below. Could any experts help explain this further?

(I have #3 in this video)

http://www.mityvac.com/user_manuals/07000-06820.pdf (page 9, "valve guides" paragraph)

 

[Turbo6Smackdown]

Who here studies vacuum readings. I know some of you do.

 

[69RSCLONE]

Not sure, but I had a broken valve spring before and had a rapid flutter in the gauge.

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[TurboTnZ06]

If you blow a headgasket on #6 completely out, you'll only get 10 inches of vacuum and it flutters just trying to keep running to get it on the trailer. Normally, 20 in, and it never flutters ever if all is good. 15 in at 60+ mph just cruising in 4th at 2000+ rpm nlu converter.