You would need to get it ported and run 14/38 gearing or modify it and run 15/40 gearing......depends on how you are beating him. You would also have to port the Vito's 240 cylinder. If it's a straight up drag, it helps to run a larger carb. You will have to beat him on peak hp as he will have you beat on low end torque no matter what you do. A stroker can help narrow that gap as well. From what I've seen Z's usually dyno around 33ish hp stock.....doesn't sound like much, but like I said.....they have Blaster's buried in low end torque from the 4 stroke engine so even if you had 33hp, you would still lose. The idea is to get above that. A ported 240 cylinder with a larger 35PWK carb in a straight line would take him if he is stock. Other things like advancing timing, head milling/rechambering, and running a stroker crank will take it farther.
youll probaly lose by 5 bikes ad he will keep pulling away cause me with a 3mil stroker , and vforce reeds ,with f7 exhaust beat him by about 2 or 3 bikes