My 1986 trans am had a motor swap from the person that I bought it from it went from a 305 carb to a 350 carb. The computer and vss buffer box are still inside the car, the only thing is there are wires in the back of the engine bay that have been cut they sit next to the distributor and back of the passanger side value cover. The ecm doesn't control the speedometer I heard, so I played with the vss buffer box. I grounded the black and white stripe wire and got nothing out of it. Then for the hell of it I got a light tester and grounded the clamp and the green and black stripe wire going to the speedo head I started to tap that and I got the odometer to move and the speedo to jump, but only when I would tap the green and black wire, the speedometer wouldn't hold. I know the 2 brown wires go to the ecm and I was wondering if they have an issue or if the bundles of wires in the engine bay need to be hooked up again, but I don't know what they were hooked up to. The ignition system was changed out. The vss buffer box has power through the pink and black wire and the vss (purple and yellow are hooked up) and the black wire is grounded and the green and black go to the speedometer. I'm running out of ideas of how to get this speedometer to work. BTW the speedometer worked before the motor swap to a 350 to a 305, so I am wondering if I need to hook anything else up. If anyone know how to get this damn speedo to work please let me know. Farthest i've gotten is getting it to jump and stop and getting the odometer working.