Here's what we started with:...
Here's what we started with: a pair of Torino-type axle housing ends, a pair of 3 x 0.188-inch wall DOM tubes, and a stock Ford 8-inch axle centersection. This had the original axle tubes cut off and turned down so the new 3-inch ones would slide over them.
When it came time to replace the closed-drive axle in my '49 Chevy-Project Purple Pig-I wanted a rearend that was strong, compact, and had brakes that would be more than accurate for the increased horsepower. Currie Enterprises put together a new 8-inch Ford axle for us, with 11-inch drum brakes, and an offset pumpkin so that the driveshaft runs straight. I went for an 8-inch over a 9-inch, owing to its smaller pumpkin as there will be limited room under the Chevy once the suspension is on full drop with the chassis C-notch, and I still have to run an exhaust system over the axle. Plus, the 8-inch is plenty strong enough for a street car.
While I'm sure only a limited number of you are going to undertake narrowing your own axle casings, it's nice to see how it's done. Having said that, it's not that hard of a job and Currie even sells an assembly alignment bar under its Nine-Plus brand (www.new9inch.com), which sells brand-new 9-inch rearend components, offering everything from gear cases and mini-spools to T-bolts, bearings, gaskets, and retainer plates. If you own a lathe you could even turn up your own collars for an alignment bar.
Seeing as I mentioned retainer plates, the 9-inch Ford axles are often described as having large [or Torino] bearings. This simply relates to early and late bearings respectively, with the earlier style having a larger bolt pattern on its housing ends, and subsequently the bearing retainer plates.
Ford 8-inch axles all came as standard with 2 3/4-inch axle tubes, usually tapering down to 2 1/2 inches at the ends, and small axle bearings. The main advantage of the 8-inch rearend Currie Enterprises fabricated for us is that the axle tubes were replaced with 3-inch tubes-meaning aftermarket axle brackets such as those for ladder bars or four-links-will fit easily, though we didn't require that facility, and it now features the larger Torino axle bearings and housing ends, allowing the fitment of 11-inch brakes-a huge improvement both aesthetically and functionally.
While the 11-inch drum brakes will likely be sufficient for our Chevy, it's good to know that these all-new brake kits use the Aftermarket Brake Configuration Standard (ABCS), which was developed to provide interchangeability. Any axle that uses Torino housing ends, 2.8-inch register (the diameter of the hole in the center of the drum) and 2 1/2-inch brake space (the distance from the outside of the housing end to the outside of the axle flange with the axle installed) can use any ABCS-configured disc or drum brake kit with no modifications. These include 11-inch Explorer and 11 5/8-inch Mustang discs, as well as Baer, Wilwood, and SSBC discs. This means a swap to discs if required at a later date will be a bolt-in swap!
Note the end of both the tube...
Note the end of both the tube and the centersection had been chamfered for better weld penetration. The tube was a snug fit over the turned-down original.
The centersection was placed...
The centersection was placed in a jig, a gear case with collars in place of the bearings bolted in place with a gasket, just like it will be when assembled, and the alignment bar pushed through the collars.
The new axle tubes were pushed...
The new axle tubes were pushed into place over the alignment bar.
Next, the housing ends were...
Next, the housing ends were installed, with stepped collars replacing their bearings.
Once leveled, the jig was...
Once leveled, the jig was tightened to hold the axle in place for tack-welding.
With the collars clamped to...
With the collars clamped to the housing ends, another tool was used to ensure they were in alignment.
The tubes and housing ends...
The tubes and housing ends were tack-welded with the alignment bar still in place, each joint receiving four welds, 90 degrees apart. This makes the casing strong enough to have the alignment bar removed and be transferred to the welding shop.
Final welding takes place...
Final welding takes place on this machine, which rotates the axle housing so each weld can be done in one continuous pass. Rollers support the opposite end of the housing.
Axle blanks await cutting...
Axle blanks await cutting to length for individual rearend requirements, after which they'll be splined and drilled in-house for whatever wheel bolt pattern is required.