[68c10airstream]

Leon, called the guy that makes this for shiftworks and he would exchange (if needed) the silver sprocket piece in the middle of the pic. He didn't disclose exchange price but a purchase without trade is $135.00. I double checked my sprocket piece (speedometer drive gear) and it is the most popular 15 tooth. I looked on ebay for the plastic driven gear (mine is 35 tooth) and they sell in the $10.00-12.00 range. if that's all you need. Major changes would require a different adapter and gear, these pairs are about $40.00 for the pair (adapter and plastic gear). I believe after checking parts for gm transmissions that the metal drive 15 tooth gear is from a turbo 400 and he adapts this with a sprocket on his own made-up sleeve with set screws. I will try and verify this tomorrow. An additional variable here is to use a ratio box (approx $60.00) to slow down and fine tune the speedo cable output from the trans. I'll try and follow up tomorrow with a summary of all possibilities, i just wanted to get some info out to you right away.