Your biggest limitation will be your heads/valvetrain/cam, as they were designed with fuel economy in mind. A friend of mine recently acquired an L99. Here is the modifications plan I suggested to him:
TransGo Shift Kit
Custom Precision Industries Torque Converter (NOT the Vigilante)
SuperStealth RamAir Intake Stage 3
Throttlebody Coolant Bypass
Ignition:Upgrade coil, wires, sparkplugs
Exhaust:Conclusions pending. Considering stock LT1 dual exhaust plus crossover, Random Technology cats, Tri-Y headers. Stiil thinking.
The exhaust should be tuned for an upper limit of no more than 300 horsepower to maintain drivability, economy, and a heathy torque band.
The heads are the big variable. A 3" stroke will rev more easily, but the valvetrain must be modified to handle and take advantage of that. Also, what kind of cam would you choose? The heads are the big question.
Finally, who's gonna reprogram it?