first I moved up from 30 mains to 35's. Pulled real nice but the plugs looked lean. Went up to 40's & lost power so I put in 37.5's today. Pulled better than the 40's but stuttered at 9,000. Like it ran out of fuel in the bowl. Anyone got any idears? I'm tired of playin with 'em, should I just get a V&H jet kit?