I converted my trans am over to 90 up speed density TPI with a 5 speed manual from a 87 iroc.

Problem, GM says there were 3 different VSS used at 80.00 a pop I don't feel like getting the wrong one, so tell me which GM part # would be the right one for my car.

Also with 373 gears and a five speed would the speedo gear from a car with 342 gears get my speedo within 5mph off, or where could I get the right gear, would a 373 5peed speedo gear from say a 84 HO f-body fit the later model speed sensor.

also I converted over to a electronic speedo it came from a 87 GTA and would the 90 up speed sensor run this speedo right or would I have to run a 90 up speedometer as well

thanks