You actually have several options, but none of them are cheap.
The shure thing is individual throddle body setup (they use the cannon manifold and look like tripple webers with fuel injectors on top (Look up itg), but it may require a new fuel injection system (ie electromotive)
horsepower and response possibilities are HUGE but what is your goal here??
How fast do you want to go.......means how much do you want to spend!! As always!!
Regardless, unless you know A LOT about flow theory and fluid dynamics, making your own plentum is a MAJOR undertaking
If your in a non smog state, pick up some carbs!!