You have enough trying to keep the b4's running. To me it is masturbation to waste all that money and time of putting that new motor in that fram never to get the full potential out of it. But to each his own .
You have a gas tank to fab up to work , a sub frame , a front end, wiring harness , pipe, gauges, fuel injection, power comander, wheels . The b4 alone is just not the right bike to be throwing 120 hp at. and also figure out how to fit a air box in there . Good luck. Sounds like major money to me.
Im not here to burst your bubble , but if you want a money pit i have a few!