with a 370 that original I wouldn't mess with it. But if you have to then some suspension upgrades would probably get you there faster. Good set of shocks can often feel like you have added 10 hp when you track and hook up harder, also you haave A forks, later model B or better after market ones would also get you going quicker.
To my way of thinking the 370 is the perfect motor..... pulls hard enough to keep traction and will rev out. Remember even one jetting change can be like night and day on a 2 stroke, so start with jetting first.