Super help with pitching velocity.?

Im a high school pitcher, and i have ok location and my season just ended. i have a just below average speed fastball and a slowish curve. im a decent pitcher but i really want to blow it by hitters now, and at this level finesse pitchers dont make it as much. Ok people so to help velocity, excercise your legs, i actually have strong legs, but i still cant get that torque on my fastball. But im 5'11 and 135 pounds does my weight have anything to do with it, and other than long toss how does excerising legs help pitching speed. and i throw 2 seam fast, whenever i throw a 4 seemer it seems to go even slow. is my 4 seemer supposed to go faster than my 2 seemer?