What is the difference between Ford 9-inch diffs?

Difference Between Ford 9-Inch Differentials
The Ford 9-inch differentials have several variations and features that distinguish them from each other. Here are some key differences:
1. Design and Performance:
– The 9-inch differentials feature larger diameter ring gears, creating additional distance between the centerline of the ring gear and the centerline of the pinion gear, known as hypoid distance. This design benefits performance from a “bigger is better” standpoint.
– The 9-inch is a dropout-style differential, with the gear set accessed through the center cover on the pinion side of the axle, not from the back like a more common carrier-type rear end.
2. Housing Variations:
– Early, pre-1966 9-inch differentials have a round housing, while later versions had a hump integrated into the housing. Ford produced different widths of differentials, ranging from 57″ to 69″ measured from the outer flanges on each axle tube .
– The Ford 9-inch housings were produced from 1957 through 1986, and the strongest production Ford 9 case is made from nodular iron, identified by the letter N cast into the inside wall or front of most of the production third members between two of the strength ribs.
3. Customization and Modifications:
– The placement and welding of the unit must be extremely precise in order to positively locate the differential. Superformance offers a variety of 9″ diff modifications, including bolt-in replacements and custom-designed narrowed or modified units.
– The center section of the 9-inch rear end is removable, allowing for easy swapping of gears or differentials on a bench. Depending on the application, the rear end may be heavier duty, made of high-performance materials, or have a locking differential.
4. Aftermarket Parts and Upgrades:
– Aftermarket renditions from various manufacturers, such as Currie, Mark Williams, Moser, Strange, and others, provide replacement and upgrade parts for racing applications, including limited slip differentials and axle shaft configurations.
These differences in design, housing variations, customization options, and aftermarket support contribute to the versatility and popularity of the Ford 9-inch differentials in various automotive applications.

What is the difference between Ford 9-inch rear ends?

Ford 9-inch rearends have a third “extra” pinion support bearing located at the rear of the drive pinion. Other rearends have only the traditional center two support bearings.

Why are Ford 9-inch rear ends so popular?

Its overall strength and availability are its greatest attributes, and 9-inch units are available with either 28- or 31-spline large diameter axles. The 9-inch rear end housings, also noted for their sturdiness, were built with case thicknesses ranging from . 150″ to .

What is the different sline counts on a Ford 9-inch?

Ford 9-inch third members come with three common carrier bearing sizes, which include 2.892-inch (28-spline), 3.062-inch (31- and 33-spline), and 3.250-inch (35- and 40-spline). Larger race versions up to 3.812-inch are available for Trophy Truck applications with 40-spline axleshafts.

How much horsepower can a Ford 9-inch rear end handle?

GearFX offers a wide range of Ford 9-Inch rear ends, with strength ratings that range from 650-hp to 1000-hp and beyond. Their most popular setups are their S- and N-Series rear ends.

What’s so great about a Ford 9-inch rear end?

The iconic Ford 9-inch has been the go-to diff for hot-rodders since day one. The brilliance of the unit is its ability to hold power, its quickness in changing gears, its vast range of available gear ratios, and the ease in which it can be setup. Shop our Ford 9-inch differential products here.

How do you identify a Ford 9 differential?

To recognize a locking or limited slip 9″ differential, look for a metal tag on one of the bolts that holds the center section to the housing. There is a gear ratio stamped on the tag. For example: The tag will say: 350 for 3.50:1 ring and pinion gear ratio.

Who makes the best Ford 9-inch rear end?

Strange Engineering is the most recognized name in the aftermarket industry when it comes to Ford 9 inch rears. From high performance street cars to top fuel, Strange Ford 9 inch housings are relied on by more racers than all other manufacturers combined.

How do I know what Ford differential I have?

Whether. It needs an additive or not usually that’s on those tags also. As far as identifying Ford. Gives most of the Fords will have the same format. So your super duties your f-150 is your Mustangs.

How do I identify my Ford 9 inch gears?

Take a string and tape it to the passenger’s side of your driveshaft. Roll your car forward exactly 1 turn of the wheel. Crawl back under and see how many times the string has wrapped itself around the driveshaft and compare with available 9″ ratios.

What is so special about a Ford 9-inch rear end?

One of the features which distinguishes this axle from other high-performance or heavy-duty domestic solid axles is that unlike other axle designs, access to the differential gears is not through the rear center cover; rather, in the Ford 9 inch, the rear cover is welded to the axle housing, and access to internals is …