Rear Axel Housing Information Needed

[Ray C.]

I am in the process of restoring a 1961 270HP Corvette. I would like to determine what rear axel ratio I have. The JG states that the ratio is determined by a notch on a 1 1/2" metal tag that is located towards the front of the case at about 2-o'clock. This tag is present at the correct location and has a notch at about 1-o'clock. There are also numbers and letters that I believe to be the date code: E 3 1 and casting number 3789812 which is correct for a late 61. There is also a large P with a small hash mark that I believe stands for a positraction unit.

Thanks for any help!
Ray

[Joe L.]

Re: Rear Axel Housing Information Needed

Ray-----

The "notched" tag signified that a 3:70:1 ratio was originally installed.

[Ray C.]

Re: Rear Axel Housing Information Needed

Thanks!

Ray Joe

[Ray C.]

Re: Rear Axel Housing Information Needed

Thanks! Joe

Ray

[Mike E.]

Re: Rear Axel Housing Information Needed

Ray--
Best way to tell?--check on the passenger side of the unit, in about the same area as the casting number/date is on the other side. There should be a shallow stamping with a two-digit letter code which indicates the ratio, followed by numerals which indicate the assembly date.

[John H.]

Re: Rear Axel Housing Information Needed

And after 42 years, what's inside the pumpkin may or may not be what was "born" there originally. Turn both brake drums (together) one full turn and count the revolutions of the pinion yoke to verify the installed ratio; 3-1/2 is a 3.55, 3-3/4 is a 3.70, etc.

[Ray C.]

Re: Rear Axel Housing Information Needed

Thanks to All!

I cleaned and inspected the right side (passenger) of the housing and found a stamping of: AN 516 or 3.70:1 ratio and May 16 date code. I rotated the wheels one complete revolution and the yoke turned almost 3 3/4 revolutions.

As always
GREAT information
Ray