I got a dumb question, would the ecm need a prom in it to run the speedo on a vss car? Mine is a 91 rs converted from tbi 305 to carb 350. stock tranny.

 

Well, since as far as the ECM is concerned, the VSS is just input to it, and the ECM doesn't run the speedometer...

 

So i can wire up the vss and buffer without the ecm and my speedo will be accurate? I have read since posting this question that some of these prom burning guys can re calibrate their speedo after a tranny swap by changing some stuff in the prom that was over my head. that leads me to believe it needs the ecm but honestly im a little lost here.