I had to go to #42 pilots and went from 182F/185R jets to jets drilled with a #43 drill bit. I was told by VFJ to go with that since I am still running the stock air filter and it seems to run very well. I think he normally suggests 3/32" drilled for most people with the 12-hole mod, TwinAir PowerFlow, and Muzzy exhaust that install the UPP intakes.