I recently installed a 3.08 rear end on a 1960 Corvette with a Borg Warner four speed. Which speedometer gear do I use. When I’m driving the speed indicator is about 8-10 miles to slow I currently have a 20 tooth gear at the moment. Does reducing the gears make it read higher or lower. The original rear end was a 3.73
Thanks...

 

Try this:


http://www.stl-vettes.com/65vette/gearcalc.htm

 

With a 3.08, you need the 18 tooth brown gear which will get it closer. To get it exact, you will also have to change the transmission internal gear most likely. That's what I did, and speedo is finally dead on now.