Tuning the TBI PCM with a Wide Band O2 Sensor (WBO2) is a very good plan. My WBO2 thread: http://www.gearhead-efi.com/Fuel-Inj...g)-Spreadsheet

Usually 8 port injectors is better than 2 throttle body injectors, wet flow intake vs dry flow intake.

Edelbrock has discontinued production on the Vortec MPFI system (part # 3506) https://www.summitracing.com/parts/edl-3506

The factory L31 intake system is an option to consider, if factory L31 horsepower / torque is acceptable?

Using a WBO2, I was able to "Tune" a 1995 Tahoe with a transplanted bone stock L31 to 260 RWHP using the Tahoe TBI PCM modified for MPFI.

dave w