It depends what it is calibrated for. It has to match the injector size you are using. If it doesn't, it'll run like crap.

 

he said all I had to do was hook it up. it came off a Mustang 5.0. i will find out what size injectors he had

 

It is off a 94 95 Stang stock motor. So what ever size was in the SN 95 stang is what it is calibrated to