What does your fuel system consist of? Are you using a mechanical pump or electric?
Currently I'm using a carter 120 street pump & just added a 1/2 inch line from tank to pump & it still leans out a bit at around 5700 - 6000.
Cliff said he had issues with the same pump not keeping up too.
I went to the track once this year & ran 12.15 @ 112 it layed down @ the top of 1st & 2nd.
Maybe the best option is to go to some kind of electric pump, but I'm trying to avoid that.