9.380 Rear need advice

[Mfee2079]

Of course my Bird has the oddball 9.380 instead of the plain old 9".
It also is an open rear with crappy 2.80 ratio.
I want to upgrade to a limited slip n a more performance 3.50
What are my options?

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[7T9_Tbird]

What year 'bird?

 

[Mfee2079]

What year 'bird?

1968

 

[7T9_Tbird]

From what I've seen online and in the yards, You may be able to adapt a 9" out of a late 70's full size ford(LTD, Cougar, Thunderbird or Ranchero). Also, outfits like Currie Enterprises can fab you a axle housing that uses the 9" center section and related parts. That, or take heart that your 'bird will get great milage on long trips!😵

 

[OneAmongOthers]

Great mileage with a 429? What is considered “great mileage for that?

 

[7T9_Tbird]

Anything in double digits.🙂 My 79 gets 12 HIGHWAY with a AOD and 3:50 gears.

 

[Birchymm]

Did you ever get a fix for this? I'm having the exact same issue. I'd like to know what fits, my gears are toast

 

[Birchymm]

No one makes replacement gears for my 69 2.80 9.375 rear end. The spider gear exploded and nuked the whole thing. Im up for aftermarket or OEM replacement, but I don't know what fits. Lower arm attachment, driveshaft, springs shocks attach points are my concern. As well as overall length. My axles are good, but I understand if I have to replace them, though they are 31 spline and I'd like to keep them. Any suggestions?

 

[Toothaker]

The Ford 9 inch center section bolts in. There are 31 spline 9 inch units out there to be found.

Edit: aternately, you could replace the 9 3/8 stock center section with a used one. Some early 70's pickups used this rear end, and there are still a few 3.5 and lockers around. Search on car-part.com.

 

[Birchymm]

The Ford 9 inch center section bolts in. There are 31 spline 9 inch units out there to be found.

Edit: aternately, you could replace the 9 3/8 stock center section with a used one. Some early 70's pickups used this rear end, and there are still a few 3.5 and lockers around. Search on car-part.com.

When you say bolt in, are you saying i can use the same housing? That sounds too good to be true, which is why I question it. I can find 31 spline 3rd member everywhere, if I could just pick one and bolt it on, that would be nice

 

[Toothaker]

Yes, it bolts into the same housing.

You will need to fix the driveshaft, since the 9 inch is a different dimension lengthwise on the car and will have a different U-jount. But the gasket on the 9 inch is exactly the same as the 9 3/8 housing.

 

[Toothaker]

Just a bit of technical jargon here. The size is either 9.375" (decimal inches) or 9 3/8" (fractional inches). Rebuild kits for these are available from Yukon Gear, and these are strong gears. What is lacking is aftermarket ring and pinion sets. There aren't any, so we are stuck with used.

 

[Toothaker]

I'm rebuilding mine right now.