The OS 7D is a great carb and with the larger throat and a bit of nitro you may be approaching David's 3bhp goal. It will be interesting to discover what the changes do to the top speed as you may be getting close to max speed. I had an Arrow .40 with an OS .40VF which was clocked (radar gun) at 122. The fastest pattern ship I ever saw was Sal Battaglia's YS powered Arrow which may have approached the 150mph figure and he loved to fly loooow!
As for further increasing your speed - more nitro and more prop pitch, less diameter. You may have to re-pitch an APC to get a 10x13 or 14.
good luck and keep us updated!