Due to limited factory axle ratios and scarcity of replacement parts, the best bet for speedo corrections on older T-cases is a speedometer adapter of some sort. Shown is a Stewart Warner adapter (called a Drive Joint by the company) that spins at a 1.12:1 ratio to slow down the speedo. Other ratios are available. We found several speedometer adapters on the Web site www.transmissioncenter.net. Check the Math Quest sidebar for more info on calculating the correct adapter ratio.