It really depends on what you need for more power. The very nature of that motor you will run out of money trying to get more than 75 HP from it. Putting some more air and fuel into the bike won't do very much at this point. They used to say there is no replacement for displacement. You could spend a few thousand with big bore and head work. But the whole bike, no matter what you spend will be worth about 3 grand all the time now.
But I am a bad person to comment on it. Even if we make our bikes "Fast" for our bikes they are still slow. That is why I have always owned more than one bike. You may look at larger valves and port modifications to help with more air and fuel. Mikuni HSR 42 may be a good match for your bike.
My Victory Kingpin is now worth maybe 5k on a good day. 90RW HP with 110 lbs of torque.
