One of cool things about a g-machine is a fat footprint. But squeezing 9-, 10-, or 11-inch-wide rims and the requisite rubber beneath stock-appearing fenders of '60s- or '70s-era sheetmetal isn't very easy.
For First-Generation Camaros, Detroit Speed & Engineering's (DSE) solution is to replace the stock rear wheel houses with wider, "deep tub" versions. These tubs provide room for rear tires up to 335mm wide but, when installed properly, give an almost factory appearance that casual observers would have a hard time discerning.
DSE's first mini-tub setup was developed when DSE's Kyle and Stacy Tucker built their famous Twister '69 Camaro. The DIY kit was launched in 2003 and to date nearly 300 sets have been sold.
We recently followed the installation of one of DSE's mini-tub kits on a yellow, supercharged '69 Camaro--a car that looks very similar to the Tuckers' Twister. The ProCharger-equipped big-block car makes about 900 hp to the tires, so the planned 335-series rear meats would not only give the car a cutting-edge g-machine stance but the enlarged contact patch will give the powerful F-car some much needed grip, both in the corners and when launching the supercharged Rat.
Detroit Speed's tubs look like the Camaro's inner wheel houses, only wider--2.75 inches wider. They are made from 18-gauge steel and, unlike so many other manufacturing jobs these days, the tubs are stamped in good ol' US of A.
In addition to the First-Gen F-car tubs, DSE also makes tubs for '68-74 Novas that, too, are nearly 3 inches wider than stock. The company also offers subframe connectors for Camaros and Novas--parts sorely needed in any powerful street machine.
Although the tubs can be purchased as a pair, we elected to follow the installation of DSE's more complete kit, which includes a new rear upper shock crossmember. The kit, which lists for about $1,300 (vs. $400 for the tubs alone) also comes with offset shackles needed to relocate the leaf springs, but as that is more or less a straightforward swap of the shackles and springs, we're focusing just on the tubs in this story.
To keep those super-wide rear skins in the newly enlarged fenders our Camaro project car also required a narrowed axle, so its 9-inch rearend was removed and trimmed about 2 inches on either side.
This is not a project for the faint of heart or someone who questions his welding ability; the DSE tubs are sized correctly, but 35 years of chassis flex on the somewhat flimsy First-Gen F-car unibody invariably means some tweaking and fine-detail metal finishing is required. Also, the rear framerails must be notched and re-boxed to accommodate the tubs and tires--a procedure that, while relatively straightforward, nonetheless demands experienced welding and metal-finishing skills.
Cutting into the stock rails also reveals the early F-cars' built-in weakness.
"The truth is the steel in those rails isn't very thick--it's more like boxed tin," says Tucker. "But while it made the F-cars prone to chassis flex, it is pretty easy to cut out. modify and strengthen."
Once in place, the new deep tubs absolutely look factory installed, particularly when viewed from inside the trunk. DSE made sure their contours match the originals, only wider. The tubs do require some minor modifications to the rear seat--a nip and tuck at the corners that still allows the stock seat cover to be used.
This isn't an instruction guide, however, as we simply don't have the space to show every intricate detail. It should, though, give you an idea of the labor involved in the project. DSE's kit comes with detailed instructions, including a video CD, so someone who is competent with a torch, cutting tool and MIG-welder can accomplish the project at home. Tucker tells us a 110-volt welder will handle the job, but a 220-volt unit is recommended.
DSE also says most enthusiasts who order the tubs tackle the job as an at-home project, while the others opt for professional help. Either way, the DSE kit takes the guesswork out of fabricating the parts and that has made entry in to the g-machine Touring ranks much more accessible to many would-be pilots.
But whether you attempt the job yourself or farm it out, use this story as the "20,000-foot" view of the installation--it provides an excellent look at the tasks involved, but we simply don't have the room to show every weld stitched.
"The best thing you can do to ensure a successful outcome is take the time to measure everything before cutting or welding," says Tucker.
That's sage advice, because once that cut-off wheel hits the tin, you're committed.
Tucker also tells us to plan on about 40-50 hours of labor for the job--figures that certainly will be skewed by the experience of the installer.
Patience and attention to detail, however, should pay off with stunning results.
DSE has a deep tub kit specific for '68-74 Novas, but the installation procedures outlined in this story apply just about exactly.