We installed the DSE weld-in subframe connectors and solid subframe bushings on our ’68 Nova at Outlaw Motorsports in Riverside, California. Our finished results look sleek and feel strong!
Early on in Project Nova’s tenure with PHR, we noticed that any time we put a jack under any of the X-body’s four corners we were met with lots of creaking sounds, tweaked doorjambs, and the three remaining tires preferring to remain glued resolutely to the ground. Throughout our suspension upgrades at Classic Performance Products, we always knew that—unless we did something—the effectiveness of those mods would be tempered by a flaccid chassis to produce less than spectacular results. What we knew all along was that some very simple, cost-effective chassis stiffening moves can produce performance gains on par with more expensive mods like we’d already done. It’s one of those things seldom spoken about when lavish groupings of parts are packaged together, but that suspension experts readily admit has a huge impact on vehicle performance.
Hard to imagine such a modest...
Hard to imagine such a modest set of parts can make such a huge difference in both the real performance and perceived feel—but it does. Shown is DSE’s subframe connector kit (with included gussets and box ends), their solid body bushing kit (stock ride height), and their stainless bolt/washer kit.
With our body restoration in full swing at Outlaw Motorsports (Riverside, California), we were presented with the perfect opportunity to easily rectify the situation while the car was blown apart. Unibody cars like our ’68 Nova benefit from a weight-reducing, cost-saving design that eschews a full frame for an integrated body/frame arrangement, but as a result, it also means it suffers from torsional instability. Moreover, this chassis flex only gets worse with age. The extreme flex in our 43-year-old car meant that the impending restoration would guarantee we’d suffer paint damage soon after rolling it out of the shop. Not wanting to chance that, we placed a call to the Nova experts at Detroit Speed and Engineering, and placed an order for their X-body specific weld-in subframe connectors, and solid subframe/body bushings. In conjunction with our planned rollbar, we could virtually eradicate all traces of chassis flex in the little Nova.
Before installing the subframe...
Before installing the subframe connectors or bushings, we gave the front stub a good hose down with Eastwood’s Extreme Chassis Black paint. This stuff is tough, and has three times the resin of traditional coating, making it both attractive and durable for the long haul.
DSE recommends both mods be done at the same time, as the weld-in subframe connectors necessarily mean you won’t have access to the body bushings as long as the subframe connectors are welded to the car. Unlike the rotted-out rubber bushings we replaced, the billet aluminum DSE ones will remain dimensionally stable for the foreseeable life of the car, while providing their own measure of chassis stiffening altogether separate from that of the subframe connectors. (The kit also comes with companion radiator core support bushings, which add a much needed measure of stability for your frontend sheetmetal, including the hood and fenders.)
DSE’s subframe connectors are somewhat unique in that they require a modest section of the floor be removed, with the affected floor area then being welded to the connectors. While the operation is marginally destructive to the Nova’s (and Camaro/Firebird’s) rear floorpan area, it’s unobtrusive. This isn’t something you want to do to a 100-point restoration, but if your bag includes any kind of spirited driving—dragstrip, autocross, or road course—the DSE subframe connectors are the best ones going, hands down. They also double as a safe jacking point, and being tucked way out of sight, have a zero visible profile. Their beefcake design also renders your Nova (or Camaro/Firebird) with a level of stiffness equal to or better than a modern car with a full perimeter frame chassis. Moreover, we’re thrilled that our CPP suspension and braking components will be able to live up to their true potential on the street, and out on the track. So go ahead, twist and shout—not out of frustration—but with the joy brought by a stiff and responsive chassis that will also keep your sheetmetal from buckling and cracking.
We start by removing and thoroughly...
We start by removing and thoroughly cleaning our Nova’s stock subframe with a power washer. Once the DSE subframe connectors are welded in, the stub frame most likely will never see the light of day again—so use the opportunity wisely.
Here are the shot 43-year-old...
Here are the shot 43-year-old body bushings. Hasta la vista, baby!
The DSE bushings sandwich...
The DSE bushings sandwich between the subframe and the body; DSE supplies four for the body, and two for the radiator core support. We saved the core support bushings for later in our restoration. The mounts are hardcoated, not anodized; DSE’s hardcoating process resists corrosion over the long term much better than anodizing.
Ron Aschtgen of Outlaw Motorsports...
Ron Aschtgen of Outlaw Motorsports lowers the Nova’s body on the subframe for reassembly. If you’re restoring your Nova, it’s the perfect time to perform these chassis stiffening moves, since you’ll likely have the body off the subframe anyway.
With the subframe aligned...
With the subframe aligned with the body, thread the bolts through the washer and the billet aluminum outer bushing shell, then into the body. Torque the body bushing bolts down to 85 ft-lb. (Core support bolts get torqued to just 35 ft-lb.) We opted for DSE’s stainless body bolt kit.
Now on to the subframe connectors....
Now on to the subframe connectors. Carefully cut out the paper template from the DSE instructions, and tape it to the floorpan from beneath. It’s key that you accurately measure the position of the template, placing it just where the instructions indicate—you’ll be cutting this portion out so you’ve got just one chance to get it right!
With the template outline...
With the template outline marked on the floorpan via a slight fogging of black spray paint, Aschtgen begins cutting out the indicated shape with a cut-off wheel. Note how the brake line must be temporarily relocated—same for the fuel line on the passenger side.
The aft end of the DSE subframe...
The aft end of the DSE subframe connector is cut with a long V-shaped channel that captures the rear subframe. The connector can then be wedged tight to the rear subframe and positioned ideally for the front gussets. Note how the connector is nicely recessed into the cut-out channel in the floorboard.
You should end up with a rectangular...
You should end up with a rectangular piece of floorboard when you’re done. DSE also makes these weld-in subframe connectors for first-gen Firebirds/Camaros, and the installation procedure on those models is identical to our Nova.
We made much use of our Millermatic...
We made much use of our Millermatic 211 with Auto-Set, which is a super easy-to-use MIG welder for the pro and the hobbyist. The dual-voltage unit uses either household voltage or 230 volts, and automatically senses the correct wire speed for the material thickness you set. Here, Aschtgen welds the endcaps to the connectors before putting them on the Nova.
The gussets are welded to...
The gussets are welded to the front subframe and the connector; the gussets have three holes for quick rosette welds, which are supplemented by perimeter welds around the gusset. The most important weld performed by our Millermatic 211 was the one connecting the gusset to the front subframe. Another gusset also goes on the inboard side of the connector.
The floorpan may need a little...
The floorpan may need a little persuasion from a hammer to close up a small gap near the front. The tighter the gap, the easier it will be to weld.
With the front solidly linked...
With the front solidly linked to the front subframe, run a MIG bead around the rear of the connector where it ties in to the rear subframe. This area is an important structure where the leaf-spring perch, body, and rear subframe all come together; the subframe connector ties all this to the front stub, bringing vehicle stiffness to the next level.
We’re nearly there—the last...
We’re nearly there—the last big operation is to stitch up the gap between the floorboard and the subframe connector. The Nova will gain a significant amount of additional stiffness by tying the subframe connector to the floor and surrounding area—something most subframe connectors do not do. The final move was to coat the bare metal with more of Eastwood’s Extreme Chassis Satin Black—both bottom and top side. With our body and paint completed, our next step is to replace the ratty wiring with a new harness from Painless Performance. We’ll bring that your way next month!
The front panel of our Millermatic...
The front panel of our Millermatic 211 has controls for wire speed and voltage, giving us the option to set it manually (to deviate for special circumstances), or go automatic. We used the Auto-Set feature, which automatically adjusts wire feed speed to the material needs. We also dig the Smooth-Start feature, which prevents popping and splattering on start-up.
The final move was to coat...
The final move was to coat the bare metal with more of Eastwood’s Extreme Chassis Satin Black—both bottom and top side. With our body and paint completed, our next step is to replace the ratty wiring with a new harness from Painless Performance. We’ll bring that your way next month!
Flash-forward a couple of...
Flash-forward a couple of months, after our Nova’s exterior paint was completed. We used a wire brush on the floorpan where it abuts the subframe connector. The idea is to clean a nice surface for welding the floorpan to the connector.