The 'Old Style' and the 'New Style' lower plenum mate to a different Head intake runner.. Old Injector, Old Plenum, Old head Runner.. all fits properly.. no bumps or steps.. same goes with all 'New Style Parts''.. If you mix and match old heads with new lower intake, the ports do not 'Match' but they will fit..
Question:.. '96 shell.. that is OBD2.. what ECU are you using.. and what year are you going to register the car as? does it matter in your neck of the woods?