370s in a mikuni flatslide will be fat with that set-up. i got +4 stroke, 68mm bore, dune port, 18cc domes , +5 timing,t-5s and 34mm TM mikunis w/ pod filters. i'm running 280 mains and its still on the rich side. thats at sea level. flatslides suck alot more fuel than a roundslide.