It's been a while since we've checked out the 9-inch rearends going together at Currie Enterprises, but you'll notice we're not calling them "Ford" 9-inchers because that designation simply isn't true. While the architecture of the housing, the third member, the brackets, bearings, and internal components are all interchangeable with an original Ford 9-inch, there isn't a single Ford part involved in a turnkey crate rearend from Currie Enterprises. While FoMoCo gave up on the bulletproof 9-inch a couple decades ago, Currie has continued to perfect it.
There's a reason that the Ford 9-inch became the industry standard for laying power down without fear of snapping parts. In its original spec, the 9-inch was developed to be a multiuse semi-floating design for family cars, muscle cars, and trucks. It is tough without a doubt, but it's the design of the centersection that really separates it from other rearends. Rather than use a bolt-on rear cover, the 9-inch has a fully welded enclosed housing, which makes it stronger. This also means access to the internals comes via pulling the gearcase and differential out from the front side. It sounds like a pain, but in reality it makes working on them much easier since everything can be done on a workbench before installing it into the housing. Plus, it also means you can have multiple gearcases set up for different purposes, ready to swap in.
The love racers have for them has led to a strong aftermarket of upgraded parts, and that's where Currie Enterprises comes in. Currie started out rebuilding factory 9-inch Fords, but now they manufacture almost every part of a Currie 9-inch rearend in-house to their upgraded, exacting specifications. Currie has built tens of thousands of custom-spec 9-inch rearends over their 53-year history and their version of the 9-inch can be found all across the hot rodding hobby in everything from drag racers to show cars. It really has become a universally accepted solution, and it's probably the only FoMoCo part that even GM and Mopar guys will proudly admit to installing in their cars.
Of course street-based muscle cars will always be the largest share of the market, and a few years back Currie noticed the majority of customer inquiries on custom-ordered rearends shared the same basic housings, axles, and specs. Most guys were just looking for a turnkey rearend that would bolt into a stock car without modifications. That's why Currie launched the crate rearend database that allows hot rodders to order a Torino-style 9-inch already tailored as a bolt-in for 27 popular cars. That means almost anyone can get the benefit of a 9-inch in a muscle car without having to make a single calculation or measurement. All you have to do is pull up www.Crate-Rearends.com, select your car, your third member, gear ratio, brakes, and you're done. Not on the list? Not a problem. Brian Shephard of Currie has told us they've done so many custom 9-inches over the years that it's quite likely they already have a set of specs in their files from a previous build that will work. Just give 'em a call and talk to a tech representative about your car.
Standard practice is to ship out the crate rearend in pieces with final assembly up to the buyer and his choice of shop, but for a very small fee Currie will handle all the assembly for you and stand behind the work. You'll pay a bit more for shipping, but that's the option we'd recommend. You couldn't ask for a better shop to build your custom 9-inch rearend than the one that perfected it.
1. New axletubes start with fresh slices from a much longer section.
2. Several options are available for Currie's 9-inch housing, but this one will use the original-style 9-Plus heavy-duty housing. Unlike 10- or 12-bolt GM housings, the third member isn't laden with the torsional loads from the axletubes.
3. Currie's technicians drive the tubes into the centersection with a few well-laid hits from a mallet to sneak up on the correct width. An alignment bar centered off a mock-up gearcase and the axle bearings maintains straightness during the process.
4. Once satisfied with all of the measurements, the tubes and brake flanges are tacked into place.
5. We have plans for this rear: it will see an aggressive suspension down the line, but all of the 9-inch specs, including leaf-spring pad angle, will retain the stock configuration.
6. After verifying the angles and measurements, the tubes and spring plates get fully welded externally and the tubes are tacked inside the housing as well. The housing rotates slowly so the builder can seal everything with a single pass from a 420V Miller welder.
7. Look at those welds! It's so clean and consistent that it looks machine laid, but it's all handled by talented craftsmen at Currie.
8. Even with one pass, all the heat generated from welding will pull the tubes out of alignment. To set everything back to straight, the housing goes to a technician and a big hydraulic press. A gearcase is bolted in and a go, no-go fixture is inserted down the tubes to verify that the tubes are within spec before proceeding.
9. Before it moves on to assembly, the straightened housing spends 10 minutes in the abrader to create a perfectly consistent satin sheen.