The rear end in the Nova is one of those out-of-sight, out-of-mind things, but honestly, this is a really special piece. My pal Mark Williams built it to my specs. It is a stock width assembly with stock style multi-leaf perches. It has a stock cover and looks pretty stock but that's where it ends (and it doesn't come cheaply either...L-O-L).
The actual case (casting) is beefed up considerably. For example, this area behind the cap in a stock 12 bolt has far less material. Between this and the huge caps (held in with Allen fasteners), there is no need for a girdle.
Mark installs chrome moly tubes in the case, and as you can see here, they're welded (360 degrees to the center section). The stock plug weld location is still there, but it's completely rosette welded.
The OEM-style spring perches have gussets welded on both sides. This prevents the perch from being ripped off the axle tube.
There are no c-clips used on the assembly. Instead, the axles are held in place on the inside with a pressed on bearing lock ring (inboard of the wheel bearing). The horseshoe shaped plate is the external bearing retainer. The actual flange is thicker than the one used on drag car (potholes and curbs happen with street cars...)
This is a closer look at the circle track style Timken unit bearing. It's designed to operate for extended periods of time, and the seal configuration is much more durable than a drag race component.
The axles are tapered. The reason for this is triangulation. The axle is far stronger in this format than a straight design.
One of the big benefits of this entire setup is the fact it uses huge 35-spline axles (the same size as a Dana 60). M-W uses an involute spline (the same as OEM manufacturers). It is created by way of a hobbing process. Most of the other manufacturers out there simply flycut the splines, and they're not as strong. FYI, a stock 12 bolt has a major diameter of 1.291-inches. This axle has a major diameter of 1.50-inches.
Because of the larger axle diameter along with the custom center section designed to accept it, there's a need for a special differential assembly. Williams uses this 35-spline Eaton Detroit Locker for the application. The Nova has 3.73:1 gear set.
During the setup, Williams even goes as far as to safety-wire the ring gear bolts.
On the nose, the pinion is a billet job. It is designed to accept a large Spicer 1350-series universal joint.
That pretty much skims the surface on the 12 bolt. If you're interested in a more detailed look at this setup, check out these two videos:
https://youtu.be/9elyTSxkUOM
https://youtu.be/m4ycRE6cMXM
I'll wrap it up here. I'll post more down the road...