The Stovebolt Site Forums The Shop Area Engine Shop Rear end gears

I'm trying to figure out what gears are in my 55 2nd. It looks like a stock rear end, but when I bought it, they told me it has 4.11 gears.

Pictures at www.novich.com/55Chevy/RearEnd/index.html

I jacked it up (both wheels) and spun one wheel. First, when I spin one wheel, the other goes in the opposite direction, and the driveline doesn't spin. After a little rocking motion with the wheel, I get the driveline to spin, and the other wheel doesn't move. One revolution of the wheel takes slightly under two revolutions of the driveline.

Do I double that to get about a 3.9 gear ratio? Was there a stock rear end with about that gearing?

My intent is to change the gears to get a little more speed on the highway, but I just haven't figured out what I'm working with.

Any info would be greatly appreciated.

Well if it's stock it'll be a 3.90 set. You could take off the rear plate and count the teeth on the ring and pinion to figure it out.

Jack up one wheel. Mark the driveshaft and the wheel. Make 2 complete revolutions with the wheel & count the turns on the driveshaft. It should be fairly close. The stock ratio as mentioned is 3:90, if it came with a factory overdrive it would be 4:11. Of course anything could have been changed over the last 50 years.
Fred