It was 1973, the last time we saw a brand-new 12-bolt rearend in a passenger car, and man, the things are fetching untouchable green at today’s swap meets. Some have argued that GM’s 12-bolt axle has some performance benefits (primarily less frictional loss) compared to the Ford 9-inch, but even so, Chevy guys have been forced to throng to the 9er for reasons of sheer price and availability.
Greg Moser and his cronies at Moser Engineering (the axleshaft guys) changed that about a year ago with the introduction of an all-new iron casting for the GM, 87/8-inch-ring-gear, passenger-car 12-bolt rearend. Now four unique cases are available to cover four popular applications (see the sidebar “What About My Car?” for specifics). These new nodular-iron housings are even beefier than the originals, the axle tubes are 3-inch/0.120-wall, plus they have bigger bearing caps and ½-inch cap bolts—yet they accept all the stock componentry.
However, we wouldn’t buy one in stock trim since Moser offers these things with significant upgrades at what we think is a screamin’ deal. The early-Camaro unit highlighted in this story included the bolt-in housing, a set of 33-spline Moser alloy axles with ½-inch wheel studs, a built-in C-clip eliminator, US Gears in the ratio of our choice (3.73:1), an Eaton posi unit, a 1350- series U-joint yoke, and a cast-aluminum-support rear cover all for $2,105.
Chill out on the sticker shock—that’s a deal compared to some of the 9-inch prices we’ve seen, and you keep your GM car all-GM. It’s also practical compared to the hassle of digging up a grungy old housing to rebuild. Skip a few options and Moser can get you into a spooled 12-bolt with axles for under $1,700. In either trim level, coil-spring applications cost a bit more.
Anyway, we’ve had this Camaro unit for months now, and it was about time to swing it under our dragstrip-mule ’67 Camaro. Follow along to learn some key points of the installation.
