Splines in a 9" rear end????

[bishop1911]

I need a little help if possible. I checked the flanges on my 67 fastback and according to info I read, if the flange has 2 holes it is one size and if it has a larger oval hole it is another. If one side has the 2 holes and ther other has the oval hole, how do I know what is in the rear axle I have? I also need to find out if there is a website that has casting number decoding for rear axles. I am not sure if the rear axle is a mustang one or not. Any info would be great. Thanks.

Jon

 

[Dark Knight]

http://www.kevinstang.com/Ninecase.htm

if it still has the factory tag
http://www.ridgenet.net/~biesiade/Fordrears.html

 

[Edbert]

----EDITED FOR CORRECTNESS----

All 9-inch flanges have 4 holes, the small ones are closer together than the large ones.

Best way to determine the ratio of your gears are to count the teeth on the ring and the pinion.

 

[bnickel]

All Mustang 9s came with 28 spline axles.

that is incorrect info. MOST mustang 9" rears had 28 spline axles but not all. drga pak cars and some regular cj's got 31-splines, most if not all boss 302's got 31 splines all boss 429's got 31 splines all boss 351's got 31 splines. a lot of the 67-68 shelby's got 31 splines etc. there were even some other odd-balls as well, i believe pretty much anything with 3.89/3.91 gears and lower (higher numerically) and any kind of locker also got 31 splines, this only applies to 67 up as far as i know, since i'm not a 65-66 expert.