Fuel injection will not make it breather any better, which is what engines are all about, air volume pumping. To make it go significantly faster, you'll need more than the usual hot rod tricks, you'll need displacement. I'll assume this is the three carb version of the Sport Jet 90?
You could punch it up to about 110 with hod rodding tricks, but these will require progressively more engine tweaking and machining skills. Paying to have this done is quite expensive, so how good are you at port matching, dialing in air/fuel ratios, relieving valve bosses with a grinder, etc?