The way I ran 370cc injectors with my factory Z31 ECU was to install my airflow sensor element in a proportionally larger intake pipe. The Z31 ECU was programmed to operate 265cc injectors, and I used 370cc injectors (40% higher flow), so I installed the airflow element in a tube that had 40% more area, which turned out to be 3.5" ID.
I dyno'd 313 rwhp with that setup and a stock L28ET (about 15psi boost).