Our resident technohead and technical editor Mark Houlahan is building a '66 Mustang hardtop for his personal enjoyment. It will be Anniversary Gold with a 289 V-8. Because Houlahan wanted his unusual steed to appear stock on the surface, using an 8-inch rear axle for the rolling stock was his only choice in the correctness department-it just made sense. When Houlahan called me and expressed his interest in a restified approach to his restoration, we talked about the rearend. We both agreed that the 8-inch differential doesn't get the credit it deserves for reliability. And for engines producing less than 350 hp, the 8-inch is a logical solution. What's more, an 8-inch was logical for Houlahan's hardtop.
When I called Ray Currie of Currie Enterprises, he had the solution for Houlahan's challenges. First, step up to a '67-and-up axle housing, shortened to the correct width for a '65-'66 Mustang. Second, grab a '67-and-up chunk and stuff it into the modified housing. And finally, fit the iron with a supersmooth limited-slip differential from Currie Enterprises. The folks at Currie make it easy because they can build a rearend to your specifications. They will also give you valuable advice along the way.
1 This is the super-eight...
1 This is the super-eight package from Currie Enterprises for a respectable '66 'Stang. The package includes a custom-made axle housing, 28-spline axle shafts, new 10-inch drum brakes, and the Currie 3.25 differential with limited-slip.
2 An exploded view of the...
2 An exploded view of the heavy-duty Currie 8-inch unit shows the 3.25 gears, a limited-slip differential, new bearings and seals, and the shims necessary to adjust the ring-and-pinion. We chose the '67-and-up casting because it has more webs and plenty of meat around the pilot bearing and shaft.
3 Ray Currie of Currie Enterprises...
3 Ray Currie of Currie Enterprises checks the axle shafts for trueness and integrity, and then fits them with new bearings. This is a 28-spline axle shaft. When we asked Currie about the stronger 31-spline shaft, he commented that the 8-inch differential would fail long before a 28-spline shaft would. We opted for the standard 28-spline shaft.
4 The difference between...
4 The difference between a '65-'66 Mustang axle housing and a '67-'70 housing (aside from width) is the axle tube size. The '65-'66 axle tube (not shown) tapers toward the flange. On the '67-and-up, it's a straight tube (shown). Currie can build you a large tube housing for your '65-'66 Mustang.
5-a Axle seals need care...
5-a Axle seals need care.
5-b Run a thin bead of silicone...
5-b Run a thin bead of silicone sealer around the seal's circumference, and then drive it into the axle flange as shown.
6 The axle flange is lubricated...
6 The axle flange is lubricated as shown with molybdenum grease. This prevents the axle bearing from corroding at the flange.
7 New Currie 10-inch drum...
7 New Currie 10-inch drum brakes make the ride. These drum brakes are 2 inches wide for better braking efficiency.
8 Next, the axle shaft is...
8 Next, the axle shaft is inserted.
9 Four bolts and nuts secure...
9 Four bolts and nuts secure the axle assembly and brake.
10 New drums are include...
10 New drums are included.
11-a Currie has a leakproof...
11-a Currie has a leakproof system for Ford axle housings.
11-b Silicone sealer is applied...
11-b Silicone sealer is applied to both sides of the gasket...
11-c ...which virtually guarantees...
11-c ...which virtually guarantees a leakproof assembly.
12 The meaty '67-and-up third...
12 The meaty '67-and-up third member is seated in place. Note the number of ribs in this casting.
13 Copper washers are installed...
13 Copper washers are installed before the self-locking nuts are installed. These washers secure the installation and keep things leakproof.
14 The rearend for Mark Houlahan's...
14 The rearend for Mark Houlahan's Mustang is ready for the 3,000-mile trek to central Florida. Currie will paint your axle housing and third member per your instructions. Houlahan's axle was shipped bare as shown and will be detailed when it is installed.