There was a time when you had to know about a well-stocked junkyard to find a 9-inch Ford rearend for a vintage Mustang. Even then, finding a 9-inch rear axle that fit wasn't easy because only a small percentage of '65-'73 Mustangs, primarily performance versions, came with the ultra-stout 9-inch rearend. The next best fit came from the '57-'59 Ford.
Ray Currie and the Currie family know rearends like no other. Currie Enterprises dates back to 1959 when Ray's father, Frank, began designing and building differentials for personnel carriers, electric carts, tugs, scissor lifts, and other specialty vehicles. By 1964, Currie Enterprises was well underway with a 5,000-square-foot building in Placentia, California. Because the Curries were into off-road racing, they began building aftermarket axles for Jeeps. By the late '70s, Currie Enterprises was building rearends for just about everything in the automotive marketplace, specializing in Ford 9-inch, Dana 60s, and GM 12-bolts. Today, Currie is housed in a 27,000-square-foot building in Anaheim.
When the availability of used 9-inch rearends became tight, Currie made its own 9-Plus line of Ford-designed 9-inch rear-axle housings, differentials, and accessories. These aren't junkyard rebuilds; they're new assemblies ready for action. Building new rearends also protects the environment by eliminating the disposal of old gear lube and unusable parts.
Last month, we began reassembly of our Project Reclaim '65 Mustang fastback, beginning with the fuel system: a 22-gallon tank from Mustangs Plus, TankArmor from Antioch Mustang Stable, and fuel lines from Classic Tube. This month, we're visiting Currie Enterprises for a closer look at the new 9-Plus axle housing and differential. Made from premium-grade steel that's thicker than an original Ford housing, the 9-Plus Hot Rod housing accepts a 3-inch tube with a 0.188-inch wall. Currie builds this ready-to-install housing with either a smooth or notched cover. The smooth cover is for pre-'67 applications; notched (with the bulge) is for the '67 and later. Because we're building a restomod, we're going with the notched housing for better strength.
For Project Reclaim, the Currie 9-Plus heavy-duty 9-inch housing is custom cut to fit a '65-'66 Mustang, but you can order one to fit any vintage Mustang. It's available with or without brakes, and you can specify which third member you'd like depending on horsepower. A stock Ford four-pinion chunk will withstand up to 350 hp. Currie's Sportsman case withstands even more.
Being installed in our 9-Plus Hot Rod housing is the Sportsman gearcase. For our application, Currie opted for a '67-vintage 9-inch Ford case. However, Currie manufactures new 9-Plus Sportsman gearcases that are stronger than original equipment. All you have to do is specify your preference.
We like Currie's 31-spline axle shafts with large, heavy-duty bearings, sized for big Fords but with a bolt-circle for classic Mustangs. The hub is sized for aftermarket wheels. The bearing isn't sealed; instead, it's lubricated from the inside by axle lube. | 
Axle shafts are splined so you can cut them to size if necessary. | 
Axle housings are sized for each Mustang application. The main measurements are flange to flange and spring perch to spring perch (centers). Currie doesn't offer an original-style small-tube axle for '65-'66 Mustangs unless it's custom ordered, which gets expensive. We like the welded-on "Currie" emblem, which identifies the axles as aftermarket. |