You should choose the size carb based on your operating rpms. If it is a runner, and you spin it upwards of 4000 rpm, you may want to run a 300 cfm, if you are making big HP, you may want a 390 cfm. If it is just a driver, rarely seeing over 3000-3500 rpm, any carb around 200-250 cfm should suit you fine. Im not sure what all sizes are offered by diff makers, so you may need to look around, and others will give input as well. A progressive 2 barrel would be sweet. Anyone know who makes them?
