Actually, it cannot be done....
If you look very closely, there's an "extension" in that frame. The tank isn't sitting up against the steering stem, it's back about 8-10".
Sorry to burst everyone's pipe dreams, but a 1k class street bike motor inside the blaster chassis isn't very likely, the blaster frame is just too slanted to allow the motor to "sit up" like they're designed to.
79xs's and Justin Naekel's (sorry for the misspelling) shoehorns are probably as close as we're going to get to having "street bike" engines in an actual blaster frame.