Does anyone know what drive gear and driven gear I need to get my speedometer correct? Its a 68 442 convetible with a TH400,3:55 gears and 15" wheels. Any info would be apreciated. Thanks!

 

Unless you plan on running just the metal wheels without any rubber, we need to know the tire diameter, not the wheel diameter.

 

Steve, do your self a favor. The next time you have the car up in the air, remove the speedo cable and housing. Count the teeth on the current drive gear. Then you see about getting the right driven gear. Do the math and go from there. You may or may not have to change the drive gear, but you gotta know the teeth count. Going by the book may not reflect what is actually in your tranny....after 40 years.

It just one guess after another until you can do the math with actual teeth counts and actual tire radii.