Strange Engineering’s C10 Rear Axle 9-Inch Install

By Rob Fortier – Photography by the Author

Why is it the Ford 9-inch is to the aftermarket rear end world what the Mustang II is to front suspension in similar context? Simply put, they work—very well, as a matter of fact. So much so, that there are companies who’ve staked their entire business off producing them for our industry for decades now.

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That said, the 10/12-bolts and Dana 44/60s of the world are by no means inferior—it’s just that the semi-floating 9-inch seems to have suited most hot rodders as a whole over last few decades, even though Ford Motor Company stopped producing them in 1986. But unlike those aforementioned companies dedicated solely to the 9-inch, Strange Engineering has catered to all walks of differential life for the past 50 years. However, what brings us here today just happens to be Strange’s C10 Rear Axle bolt-in 9-inch assembly for 1967-1972 Chevy/GMC half-ton pickups (also available for the first-gen 1960-1966 and SquareBody 1973-1987 models as well).

Here’s our center(section) of attention for the month: Strange Engineering’s C10 Rear Axle 9-inch assembly, shown configured accordingly with Classic Performance Products’ complete Totally Tubular coil-over conversion trailing arm kit, ready to rock and roll!

Out with the old—once we disengaged the ‘bag system, remaining suspension mounts, brakes, etc., the modified-stock 12-bolt/trailing arm rear rolled right out as one unit.

Now we (the collective “we”) spent a considerable amount of time deconstructing the previously installed airbag setup and all the associated brackets/mounts welded to the frame—it was a mess, but nothing a couple-few grinding wheels and flap discs and reciprocating saw blades! One of us really needed a couple-few cold ones after that … the other needed to charge his camera battery!

The great thing about Strange’s bolt-in assembly—besides being manufactured by one of the best in the business—is just that: it’s a true “bolt-in” rear end! Unless you’ve got a set of particularly wide or weird-offset rear wheels, there’s no measuring to do, no differential configuration or research necessary; you just place your order, specify what gear ratio, etc., and wait for the freight truck to arrive with your new purchase. Once it has—bolt that sucker in and go!

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Such was the case with our 1969 C10 that, unfortunately, had been hacked up with a less-than-impressive airbag install. So, along with ditching the leaky, worn-out factory 12-bolt with Strange’s more-than-impressive 9-inch, we opted to go the extra mile and make the bolt-in install a coil-over conversion. To do so, we obtained Classic Performance Products’ Totally Tubular C10 trailing arm kit—complete with forward mount crossmember, Viking dual-adjustable coil-overs with tubular upper coil-over crossmember (which, although requiring that we trim out a substantial portion of the previously incorporated inner C-notch plate—not a problem—conveniently situates “below the bed line”, not requiring any modifications to the bed floor for clearance), Panhard, and CPP’s beefy, non-rust-inhibiting tubular trailing arms.

With the C10’s frame shaved and cleaned of unnecessaries, we could finally start on the assembly process and rear end/suspension component installation. If you’ve ever wondered what the “bent-lip” portions of framerail on a C10 chassis were for, it’s one of the things Chevrolet did for us to ensure R&R’ing a “riveted” forward trailing arm crossmember wasn’t too difficult! CPP’s heavy-gauge steel crossmember bolts right in using the remaining holes left from the stock unit’s (now removed) rivets.

We initially hung the Strange 9-inch with the CPP Totally Tubular coil-over conversion trailing arm kit pre-assembled (as the lead-in image illustrates). For now, since CPP’s lower coil-over mount brackets offer a multitude of height settings (on top of the coil-over ride height adjustability itself), we’re going with their 1-inch lowering blocks rather than the deeper 2-inch.

As for the rear end itself, our order placed netted us Strange’s nodular-iron S-case centersectioned, 31-spline traction-lock differentialed, 3.70-geared 9-inch, complete with Daytona aluminum pinion support, chrome-moly yoke, large-bearing 31-spline alloy axles, and Strange’s attractive, 100-percent bolt-in housing. (Note: CPP’s trailing arm kit will not work with the factory Panhard configuration: when ordering a Strange C10 Rear Axle 9-inch assembly, please specify “no Panhard mount” unless you want to be left with the task of removing it!)

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