Steeda custom tunes and tuners are intended for OBD2 applications only and will not work with ODB1 models. Stock first gen mod motors will respond nicely to a tune though it's recommended to upgrade the intake and exhaust system for a significant seat of the pants improvement. Steeda has been involved with tuning since they early days of fuel injected 5.0 H.O. motors and can assist you choosing your tuner and tune combo.