I've never posted anything here before, so I'm not sure I'm doing this right.
But here are a couple of links for these tubes. Not much info at these sites, but a little at leaset
They are radar tubes from wwii era. The 327a was used in SC-2 shipboard radars. I found quite a few links googling for SC-2 including some manuals for operating these sytems. Perhaps you can find something in one of those.
http://www.tubecollector.org/327a.htmhttp://home.comcast.net/~nwilson343/tubes/15r.html