Classic Truck Performance

As seen in the October/November 2020 Issue of Classic Truck Performance magazine!

Text and Photos by Rob Fortier

Why is it the Ford 9-inch is to the aftermarket rearend 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.

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 the 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 1/2-ton pickups (also available for the first-gen 1960-1966 and Squarebody 1973-1987 models as well).

Related: Week To Wicked 1970 C10 With 700 HP LS7

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” rearend! 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, and so on, and wait for the freight truck to arrive with your new purchase. Once it has—bolt that sucker in and go!

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 coilover conversion. To do so, we obtained Classic Performance Products’ Totally Tubular C10 trailing arm kit—complete with forward-mount crossmember, Viking dual-adjustable coilovers with tubular upper coilover 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.

As for the rearend 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!)

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 coilover 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 couldn’t fix! One of us really needed a couple-few cold ones after that … the other needed to charge his camera battery!
With the C10’s frame shaved and cleaned of unnecessaries, we could finally start on the assembly process and rearend/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.
Just as easily as the old came out, the new went in! Now it’s time to set the C10’s ride height and suspend it properly with the Viking dual-adjustable coilovers supplied by CPP.
The Viking Performance dual-adjust (compression/rebound) coilovers offered by CPP provide up to a 5-inch drop (from stock) themselves—even more when you factor in their new variable configuration lower mounts—and include thrust bearings to facilitate ease of coil spring load adjustment.
The collective “we” ultimately included my son when it came to installing and setting up the coilovers on the C10’s new Strange 9-inch. And I will say, junior caught on quick—with the installation aspect, not his father’s documenting process!
As mentioned, the CPP tubular trailing arm kit will NOT work with the OE track bar (Panhard), as it facilitates its own via the right-side trailing arm mount. Nonetheless, a Panhard is absolutely necessary in order to properly center the rearend—and keep it centered! We opted to use CPP’s adjustable setup.
For final ride height adjustment, we’ll hold off till the bed’s back in its respectful place atop the C10’s rearmost frame—but for now, couldn’t be more pleased with the outcome, especially the factory-like fit of the Strange Engineering 9-inch! And as Strange themselves put it, “Because Better Matters!”
Looks like these two couldn’t be more pleased that the install’s finally over, too! Good job boys!
Click an Icon Below to Share!

Related Posts