Rear End Installation - Punching Your Dance Card - Tech

After A Month Behind Bars, The Purp Gets Cozy With A Strange Rear End

From the March, 2011 issue of GM High-Tech Performance

By Justin Cesler

Photography by Justin Cesler

When we last left The Purp, Matt LaRue and Troy Pirez Jr. of ProFab Performance were putting the finishing touches on our Chris Alston Chassisworks rollcage. This month, we were on hand to witness The Purp's rear end and suspension install, two crucial systems that are much more expensive to do twice, than to do correctly the first time. Years ago, adding a fortified rear to a fourth-gen was a real chore, so we shouldn't take for granted how many excellent choices are now on the market. From stock to aftermarket GM 12-bolts, Ford 9-inches, homebuilt 8.8 conversions, and even the new Strange S60.

Built off of the incredibly strong Dana 60 design, a rear-end that has been taking heavy abuse since World War II, the S60 from Strange takes everything heavy-duty from the original rear and combines it with technology from the modern age. Built from a strong, nodular iron centersection, the S60 features a massive 9.75-inch ring gear, making it over 2 inches larger than a stock 7.625-inch 10-bolt and even larger than the offerings in a 12-bolt (8.875-inch) and the Ford 9-inch (at, you guessed it, 9 inches). According to Strange, "The S60 is stronger than any 12-bolt, even ours," so you know it means serious business.

But, the strength doesn't stop there. When Strange designed the S60, it made some key changes to the case, axle tubes, and axles, which help it stand apart from the crowd. Most obvious for anyone bolting the S60 into a late model F-body is the inclusion of a beefy torque arm mount cast directly into the centersection. This alleviates having to run a bolt-on bracket, or flimsy welded piece, and gives the torque arm a solid place to transfer power. Inside the centersection you will find upgraded main caps, which are much larger than the original Dana 60 design.

The axles tubes, which measure in at 3.150 inches in diameter, are fully welded to the housing, which makes them stronger and less prone to breakage. Depending on your goals, you can order 35-spline or 40-spline axles, although we stuck with the 35-spline units, which should be plenty strong for our needs. Either way, you can option for M12x1.50-inch, 1/2-inch, or 5/8-inch studs, depending on your e.t. goals and wheel preference. We opted for the 5/8-inch studs, for increased safety and less worry down the road.

Of course, all of this strength doesn't come without some weight, but surprisingly the S60 isn't as heavy as you would think. Compared to a similarly optioned 12-bolt, the S60 is only 25 lbs heavier and just 15 lbs more than a 9-inch. Of course, depending on your setup and goals, there may be other options that make more sense, but for where we plan on going, the S60 seemed perfect.

To offset some of the weight, we decided to install a couple of key tubular suspension pieces from BMR Fabrication, many of which you should already be familiar with: a tubular Panhard bar, adjustable rod-ended Lower Control Arms and BMR's tried and true Xtreme Anti-roll kit, which we tied into a set of boxed subframe connectors. To see how everything goes together, keep reading and make sure you tune in next time, as we should have The Purp back on the ground and rolling on a brand-new set of race wheels and tires.