We are talking about two different things.
Mechanical injection and Electronic injection
THis is not a 100 percent true but lets draw the line, Mechanical is for all out hp. Electronic is for ease to street a engine to be calm and cruise around.
First off, think about if you can afford to upgrade the driveline to a 1000-1500hp blown alky injected bbc mech injected engine. WHen that input shaft, axle shaft or driveshaft lets go, engine over revs for a sec and boom! This does require a mechanical pump.
Im guessing your electronic injection gas engine will make atleast 200 hp that you can drive around on the street. Considering fuel and boost will have to be way down.
Your carbs right now sound like your happy medium for hp and parts and what you are trying to do.
Also do you h ave a racing blower or a street blower?