Car is a 1991 Firebird BBC swap with turbo 350 trans. My speedometer doesn’t work. Guy who built car passed away so I can not ask him. Included in the parts I got when I bought it was a GlowShift gm adapter wire, with the speed sensor already installed in the trans. There is only stock gauges in the car. The stock plug doesn’t fit the sensor, could I splice in the GlowShift plug to have the speedometer work? Or should I just buy a GlowShift gauge and run the wire. This is my first project car so I’m learning as I go.