If your Meticulous and Precise at what you do just like ME i would take the carbs off ....1 at a time........like (fastrthnu) said it's much easier and it gives you a chance to see what your carbs look like, gives you a chance to clean them, check floats, etc. I live right at sea level and i'm running 280 with double K&N Filters one off each carb with Toomey T5s with some more stuff. Given where your located i would try the 290.