9 1/2 inch rearend?

[FordTruck]

I was running the few numbers i could find one rearend of my 70 because there is no tag an they came back as a 9 1/2 inch. Ive never herd of one before but everything looks alot bigger compared to the 9 in my other 70. Can anyone school me on this rearend ?

[Nitekruizer]

I don't know about 9 1/2", maybe. They did make a 9 3/8" rear end. I have one. It's in my '70 Mercury (full-size car). AFAIK, the 9 3/8" was used in full-size Fords?, Mercurys and Lincolns in the early '70's. I think they were also used in F-Series pick-ups as well. They kind of look like a 9-inch Ford, not exactly but sort of.

[ultraranger]

You would be better off with a 9-inch carrier. There is no Ford or aftermarket support for 9-3/8" ring gears.

If you really wanted a strong 9-inch 3rd member, get a an N-case. It is the ultimate Ford 9-inch case due to its high nodular iron content.

A couple of factory N-cases I have:




This one is the Daytona version which is even stronger than the first N-case pictured above.




This is a 9-inch drum brake rear end I had gotten from a 1980 Mercury Monarch to install under my '68 Mustang. The single-vertical ribbed C7AW 9-inch case is a strong unit, but not as strong as an N-case. I designed some adapter brackets for the Monarch 9-inch rear end to replace the factory 10" drums with a set of 11-5/8" diameter ventillated disc brakes from a '94-'04 Cobra Mustang and I swapped the 3rd member out for one of the N-cases I have.

9-inch rear end as it looked when I pulled it from the '80 Monarch:




The following photos are of the same rear end housing (pictured above), after I cleaned up the housing, fabbed up a new 3/16" hardline and installed the Cobra rear discs:

1.

2.

3.

4.

5.


A 9-inch 3rd member will fit in place of a 9-3/8" 3rd member. The 9-inch has a whole host of parts availability that the 9-3/8" does not.

[rusty2872]

ultraranger,

what cars/trucks can you find that N-case third member in? Is that really that much stronger than a stock F100 unit?

[ultraranger]

ultraranger,

what cars/trucks can you find that N-case third member in? Is that really that much stronger than a stock F100 unit?

The Ford 9-inch N-case, as I mentioned earlier, is the ultimate in strength for a 9-inch 3rd member. Both the N-cases I have came from mid-'70s Ford pickups. The (even stronger) Daytona N-case is a 3rd member I pulled from a '75 model 4-WD pickup that had a manual 4-spd with a granny low. They can also be found in trucks that had a factory towing package.

They are not super common in the wrecking yards anymore since people usually know what they are when they see them and snatch them up, or sadly enough, they get sent through the crusher. However, if you look around you may be lucky enough to score one. Otherwise, you would have to buy one new from Strange, Moser, or Curries.

Some links from my website that explains some of the history of the 9-inch, factory differential types and the differences in the three major 9-inch case designs Ford produced.
1. http://ultrastang.com/info1.php

2. http://ultrastang.com/info2.php

3. http://ultrastang.com/info6.php

[BobbyFord]

But, the 9 3/8" is plenty strong. I have a Strange nodular in the garage and haven't needed it.

[ultraranger]

But, the 9 3/8" is plenty strong. I have a Strange nodular in the garage and haven't needed it.

Good piece (Strange N-case) to have. I wouldn't get rid of it. If something goes wrong in the 9-3/8" or it just simply wears out, that's the end of it --it will only be good for a trot line sinker at that point.

There's no gear support for the 9-3/8" and there are no pinion shims available for them. The input driving pinion is longer than the 9-inch driving pinion and it mounts lower on the 9-3/8" case as compared to the 9-inch drive pinion's housing. 9-inch drive pinion & ring gears will not swap into the 9-3/8" 3rd member.

[BobbyFord]

But, the 9 3/8" is plenty strong. I have a Strange nodular in the garage and haven't needed it.

Good piece (Strange N-case) to have. I wouldn't get rid of it. If something goes wrong in the 9-3/8" or it just simply wears out, that's the end of it --it will only be good for a trot line sinker at that point.

There's no gear support for the 9-3/8" and there are no pinion shims available for them. The input driving pinion is longer than the 9-inch driving pinion and it mounts lower on the 9-3/8" case as compared to the 9-inch drive pinion's housing. 9-inch drive pinion & ring gears will not swap into the 9-3/8" 3rd member.

Oh, I'm aware of the differences, but if there is nothing wrong with the unit there's no point in swapping it out. They are also limited to gear ratios. Some Lincolns had them with very tall ratios. I have a 2.80-something, 9 3/8" in my Mustang right now. Some 4WD's had them with some really short gear ratios.
Incidentally, someone gave me the Strange housing for free. It was out of a full-floating race set up and came with some wicked short gears and 40 spline Pro Race gun-drilled axles.

[ultraranger]

Best I can remember, the 9-3/8" rears were limited to a 4.11 gear as the lowest ratio available for them.

That was a good score on the Strange 3rd member! If the 9-3/8" ever dies or just wears out on you, you'll have a really good back up waiting to take its place.

[BobbyFord]

...That was a good score on the Strange 3rd member! If the 9-3/8" ever dies or just wears out on you, you'll have a really good back up waiting to take its place.

Yeah, I sure lucked out. It pays to have gearhead buddies