this set up works best for my bike. 120 mains, 40 pilots, I run a Mac 4 into 1 headpipe with a 28" long Thrush glasspack 2 1/2" in diameter. This runs ever so slightly rich, idles well, and will get the power to the rear wheel. I use a mercury synchronizer to fine tune and balance the carbs. My stock mains were 110, no power.