I would run anywhere from a 5:63 to a 5:97,now I've only run a midget at the track since it was redone and i'm basing this off of what gear we ran with the midget.It sticks in my mind that some friends of mine running a sprint car there told me that was the range they were in.If you ran there with a 6:13 and were turning 7700rpm,Iwould say if you went to either a 5:75 or a 5:83 that should put you in the RPM range you're looking for.
Hope this helps you out.