so the biggest jet that comes with these carbs is too small, it's like a 90. it's cutting out at high rpm because it's too lean. your elevation will be dependent in the end of how big a main jet you really need but the standard size I always start with on those carbs with a basic stage 1 motor is a 120 main jet. I never have to mess with the pilot that comes in the carb, it always does fine, only mess with the fuel screw on the bottom in order to achieve best responsiveness off idle.