Tuning the 1996 "Black Box" computer can be EXTREMELY challenging, because Tuning Software like HP Tuners or EFI Live DO NOT support the 1996 " Black Box". Some 1996 "Black Box" vehicles owners with modified engines like yours have upgraded to the newer 12200411 PCM: http://www.gmtruckcentral.com/articles/12200411.html ... and ... http://www.gmt400.com/threads/122004...0-trucks.9644/

The 12200411 PCM is the Ultimate Solution for "Tuning" your modified engine!

dave w