Question for the diff experts - 9-3/8?

[hvywrench]

I have what seems to be a 9-3/8 diff that I've disassembled and cleaned up. It is from a '68 Galaxie, CT State Police car. Had 31 spline axles if my counting was correct.
I didn't know that it was a 9-3/8 unit until I started researching some of the numbers for bearings and such, then I measured the ring gear....
I did a bit of internet research and that sort of just confused me more.
If what I was reading is correct, there is a WAB case that is normally the 9-3/8 and it isn't supposed to be compatible with much of the 9" stuff.
Here are the pics: I have a C8AW-4025-A case and a C8AW pinion support. I laid a paper housing gasket over the case flange and it seems to line up fine. It also has the curved external rib at 1o'clock
Can this case be built as a 9"? or is it kind of a one-off that isn't usable?
Thanks for any opinions/facts/knowledge.
Bill

[thatdarncat]

That is a 9 3/8”, Ford used them quite a bit starting in ‘66 on a lot of the bigger cars with bigger engines, the more “performance” cars kept the regular 9”. There aren’t a lot of optional offerings for the 9 3/8” out there, as far as gears & differentials. The good news is you should be able just to put a 9” 31 spline pumpkin in your car. I’ve seen a couple people comment in the past that they thought there were issues with getting the stock 31 spline axles to work with a 9” pumpkin, but we’ve done a couple and there have been no issues. A few years ago we did the swap on my ‘69 T-Bird a friend of mines races. After pulling the 9 3/8” pumpkin we put the axles back in place and verified the space between them, then double checked the clearance and spline engagement on the 9” and it was fine. That is what I would advise, and I think you’ll be ok. I don’t think it’s possible to use the 9” differential parts inside the 9 3/8” case. You will probably need to re-use the 9 3/8” yoke if you’re keeping your existing driveshaft.

[hvywrench]

Thanks for that info.
I worded my question poorly, sorry.
I was thinking of building this carrier as a spare pumpkin for my '64, the '68 is long gone.
You've confirmed what I took away from my internet searches....this is basically heavy metal, not a candidate for what I was hoping.
Much appreciated.
Bill