I am putting a '65 BS ST400 in my '65 Wildcat. I am also installing a 3.42 posi rear. The car originally had a ST400 BJ with a 3.07 single track. I'm guessing the trans came out of a '65 Riviera GS but I am not sure. I am wondering how far my speedo will be off. I attached a pic of where the speedo cable attaches and I am guessing the numbers have some meaning. If the trans is out of a Rivi GS and it had a 3.42...will the speedo read correct? I know tire height will have some effect. Thanks Rick
Should be correct since trans was matched a 3.42 rear gears. Numbers on housing indicate that will accept those gears (numbers represent tooth count on gear)
Rick if you want to be sure, you need to know the following information. Rear gear ratio, tire height, and number of teeth on the speedo drive gear. The speedo drive gear is on the trans output shaft. If you remove the speedo gear sleeve, and driven gear(what you have pictured), you will be able to see the drive gear. It is a helical gear (like a distributor gear). By rotating the output shaft, you will be able to carefully count the number of teeth. Then put the numbers into this website calculator, and it will tell you what driven gear you need. http://www.tciauto.com/tech_info/speedo_gears.htm
