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When Chevrolet introduced the Chevy II for the 1962 model year, the idea was to deliver a compact car that would give the strong-selling Ford Falcon a run for its money. Development spanned just a year and half from start to finish, and the intent was to deliver something simple and affordable – basic transportation in the truest sense of the term. But as the muscle car craze start to take shape thanks to the successful debuts of the Pontiac GTO and Ford Mustang, the Chevy II’s place in the Chevrolet lineup began to shift. By 1965, Chevy’s modest runabout was available as a bonafide hot rod with a 327 cubic-inch small-block V8 under the hood and four-on-the-floor manual transmission in Super Sport guise.
Thing is, the Chevy II’s original mission had ultimately limited its performance potential in some important ways. In first generation cars, it meant that the widest rear tire that would fit under the factory chassis and fenders was 235 millimeters. Although revised bodywork would slightly improve the situation for the second-generation cars, gearheads were still stuck with a rear tire no wider than 255 millimeters for 1966 and 1967 models.
Classic Chevy IIs like our clean test-fit car make for fantastic hot rodding material. Unfortunately, there isn't much room out back for large tires. In the Chevy II's first generation, 235mm tires were the largest you could fit. 1966 and 1967 Chevy IIs could fit up to 255mm tires at the most.
As big horsepower has become more readily accessible in recent decades, the platform’s limitations have become an increasing source of consternation for would-be builders. Fortunately for the rest of us, Kyle Tucker – the founder of Detroit Speed and Engineering – happened to be one of them.
“As with most of our products, the first mini-tub kits that we developed were for the first-generation Camaro – 1967-69,” says Detroit Speed technical engineer Dan Oddy. “Not long after that we developed a kit for the second-generation Camaro, along with the ’68-’74 third-generation Nova. And when we started developing the Chevy II product line ten years ago or so, one of the things at the top of the list was a mini-tub kit. These cars definitely need some more room under there for larger wheels and tires.”
One look at the underside of the Chevy II will show you why mini-tubs are necessary for fitting larger rubber in the rear where it is needed. Not only are the rear wheelwells narrow, but the leaf spring perches are butted up right next to the brake drums.
Tucker’s background as an engineer on GM’s Corvette development team has always kept General Motors’ vehicles at top-of-mind for Detroit Speed, and Oddy says that customer feedback made it clear that there was a demand for a DSE mini-tub solution for the Chevy II platform. But the real catalyst to bring a new solution to market may actually have come from Tucker’s own garage.
“For a while Kyle had his eye on this ’63 Chevy II that was out in Michigan, and eventually he was able to acquire that car,” Oddy says. “It was pretty much a factory-stock example, which made it a good foundation for development, and it basically became our test car for the products that we were designing for the platform.”
The Detroit Speed Mini-Tubs are stamped from 18-ga steel and once installed, will add 2.5 inches to the depth of the wheelwell by enlarging the inner panels. This, combined with Detroit Speed's Spring Kit, will open the wheelwells enough that you will be able to accommodate 295mm wide tires on 1962-65 cars and up to 315mm tires on 1966-67 cars.
As with the majority of Detroit Speed’s products, these mini-tubs are largely geared toward street-driven projects with a pro touring flavor, along with those who’re looking to bring modern performance and handling to their vintage rides on autocross courses and at track days. “Some folks like these for drag racing, too – the tub allows you to get a good-sized slick under there,” Oddy notes. “But this is a nice, OEM-looking stamped steel piece, so in some ways it’s almost more appropriate for a show car.”
The Detroit Speed mini-tub kit for Chevy II applications features inner fender housings that are made of 18-gauge steel which provide an additional two and half inches of clearance over the factory configuration. That in turn allows builders to shoehorn rear tires as wide as 295mm into first generation cars, or up to 315mm on 1966 and ’67 models, thanks to Chevrolet’s revised fender design on the second-generation vehicles.
“From the factory there’s an outer and an inner tub on these cars – here we’re replacing the inner tub, which would go up against the frame rail in a stock Chevy II,” Oddy explains. “And usually that inner tub and frame rail are the factors that limit how much wheel and tire you can get under there. With the Camaros we kind of notched into the frame rail to put that new inner tub in, but with the Chevy II there’s so much frame rail there that we basically made the inner frame rail into the outer frame rail, so you’re basically gaining a frame rail’s width on each side. And because the inner frame rail has now become the outer frame rail, we need to box that frame rail back in to give it strength. With either our Quadralink systems and or our new Chevy II mini-tub leaf spring kit, we provide you with everything you need in order to do that.”
When combined with the Detroit Speed Mini Tub Spring Kit, you can see just how much room opens up underneath the Chevy II for larger rubber. 1962-65 cars can tuck 295mm tires, while 1966-67 cars can fit up to 315mm tires.
With the Quadralink system the upper shock mount is integrated into the frame rail piece, and it is designed provide the necessary room for the DSE mini-tubs right out of the box. “But not everyone needs a coil-over four-link suspension in their Chevy II,” Oddy points out. “So we also developed this leaf spring kit which moves things inboard in the same way.” The Chevy II mini-tubs also include laser-cut frame rail closeouts for builders who may want to use this mini-tub kit a non-DSE suspension system. “Those plates are going to give you that profile of the frame rail that you’re cutting into, and then you can re-box it up toward the inside of the frame rails.”
While the ability to stuff wider rubber into a Chevy II’s rear fender wells is obviously the headline feature here, Oddy says that his favorite aspect of the kit might actually be the OE-like presentation. “A lot of times you’ll open up a trunk and see some goofy-looking tubs in there and it’s immediately obvious that it didn’t come from the factory that way. But with ours, it looks like a stock piece – if you didn’t know anything about the car, you would think that it’s the inner fender that came from GM.”
The amount of extra modifications that will be required with the installation of the mini tubs will be minimal. Naturally, there will be the necessary rear subframe modifications that are a part of the Spring Kit. There are narrowed fuel tanks coming soon for both carbureted and EFI applications. And as seen here, the rear seat upper section's frame will need to be modified to fit around the rear tubs.
Builders who’re looking to run a full-length exhaust system should note that a narrowed fuel tank will provide the necessary clearance for the system to make its way to the rear bumper after the mini-tubs have been installed, but those who’re running a side-exit system or dumps can just stick with their factory-style tank.
The Chevy II mini tubs, leaf spring kit, Quadralink systems, and narrowed fuel tanks are all available to order a la carte right now. The Chevy II mini-tubs and leaf spring system can also be ordered as one all-inclusive kit in order to keep things simple. “With the Camaro system we noticed that a number of folks who initially started with the leaf spring kit decided that they wanted to step up to the Quadralink system five years or so down the road,” Oddy adds. “So we wanted to make sure that we were providing our Chevy II customers with the flexibility to approach this however they would like to.”