"Plain Jane" 1970 Nova Build

[Arrowsmith]

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...

[dykstra]

Damn Wayne! Plain Jane has the Kim Kardashian of rear ends!LOL

[Arrowsmith]

L-O-L…Yes! Just as pricey, but much lower maintenance 🤣

[EZ Nova]

Nice set-up there Wayne, Pretty close to mine in my 69 Nova, but mine is a spool and is 66/67 Chevy II width so a bit narrower. Got a deal on it used as people didn't think the 12 bolt should be in a 7 second car (car was running 7.65 with it when I bought it off him due to twisting axles).

What did you do for rear shackles? My 69 runs Smith bars and there split mono's with Afco's rear sliders. Like to see what you did with the rear to what others told me to do if I kept the shackles and not the sliders.

I haven't ran the car at the track with that set-up yet. Maybe this summer who knows with life. Car has run 10.40's with a nice L78 with ported heads and a small comp solid roller, M21 and 4.56 in the stock '69 12 bolt and spring set-up.

Waiting for results when the weather breaks.

[Pro Stock John]

Originally Posted by EZ Nova

Nice set-up there Wayne, Pretty close to mine in my 69 Nova, but mine is a spool and is 66/67 Chevy II width so a bit narrower. Got a deal on it used as people didn't think the 12 bolt should be in a 7 second car (car was running 7.65 with it when I bought it off him due to twisting axles).

What did you do for rear shackles? My 69 runs Smith bars and there split mono's with Afco's rear sliders. Like to see what you did with the rear to what others told me to do if I kept the shackles and not the sliders.

I haven't ran the car at the track with that set-up yet. Maybe this summer who knows with life. Car has run 10.40's with a nice L78 with ported heads and a small comp solid roller, M21 and 4.56 in the stock '69 12 bolt and spring set-up.

Waiting for results when the weather breaks.

12 bolt is good for drag racing until it ain't. A buddy ran his into the high 4's in the 1/8th. Another buddy is running 8.70's with his 12 bolt and his 31 spline axles were twisting, so ordered another set for this season and next winter he'll decide if he goes 9".

[EZ Nova]

Originally Posted by Pro Stock John

12 bolt is good for drag racing until it ain't. A buddy ran his into the high 4's in the 1/8th. Another buddy is running 8.70's with his 12 bolt and his 31 spline axles were twisting, so ordered another set for this season and next winter he'll decide if he goes 9".

Usually a 9" is a Hp robber and will slow him down. He would probably be better moving up to 35 spline 12 bolt. We IRHA National record holding B/D I crewed with, ran for many seasons with a 12 bolt running 7.40's in the 1/4, but light car dragster. Tried a 9" and slowed 7 hundred with no other change.

Now with that being said, weight, power and type of power adder all play a part in the strength handling of a 12 bolt. A car with a turbo will help a 12 bolt last better then a big nitrous motor.

With a 9", when really getting after it and making it the best, with do a whack of different mods, cryo and lighten gears, Ti bolts, Indy/Dewco center, ceramic bearers etc.

[CamaroNOS]

Amazing, we could only be this fortunate to be able to see "inside" your build.

I see a lot of guys making a bunch of notes as they read the fine details. There definitely will be a few of our cars out there running quicker than ever.

The detail is staggering and thank you for sharing this with us. Please keep teaching us.

Paul

[CamaroNOS]

Originally Posted by dykstra

Damn Wayne! Plain Jane has the Kim Kardashian of rear ends!LOL

Just read this.....lol.....how true.

Paul

[cook_dw]

This is an impressive modern day modified car. Very clean and reversible if ever wanted; although I never would. Well done.

[Pro Stock John]

Great build. I've occasionally seen cars like this pop up.