Also 2-to-1 exhaust would optimize mid-range torque and have less flow in high-end. Way to match fueling is to have needles without sudden change at end but more gradual taper to thicker tip. This adds fuel to mid-range and removes from high-end. Then adjust mid-range by clip-position or washers.
One way to test is to run without exhaust and see if it makes it past mid-range stumble.