If you are going to be building a boosted motor, I very highly doubt that the exhaust and intake or cam will be remaining stock peices.
The injectors are no where near maxed out on a factory TBI unit. The TBI system comes from the fatory set at ~12 PSI. The injectors have no problem running up to 40 PSI. $30 for the new regulator, spring, and diphragm, your stock 90lb BB injectors are now flowing 150lb+.
The 454 units are 50mm bores, good for 700 CFM. If you want, they can be reworked into 54mm bores, and flow 850+ with ease.