Shane,
I haven't seen a specific standard for lane 4, however, some of the Firebirds running high 12's use that lane, all the way up to 10-second Nova's, 8-9 second altereds, etc. I don't think they enforce it tightly, as the whole purpose on Friday nights is to have fun!!
Another nice part of Race City, is that most of the track personnel will let you race against whomever you wish...you just need to be lined up in the same lane, consecutively.
As I recall, from last summer you run in the 10's, correct?
Neil.