Project Swinger Nova Update: Room for Wider Tires, a Stiffer Frame, and a Patch Job

Our Swinger Nova project has gotten a lot of attention to the chassis over the past few months, including Ridetech’s Street Pak Challenge suspension kit, a Currie rear end, and a set of SSBC brakes. With the underpinnings coming along, it was time to attack the sheetmetal, starting with a Detroit Speed wheel tub kit to accommodate wider tires in back, a pair of their subframe connectors to stiffen the chassis, and a firewall cover plate. Classic Industries stepped up to help us take care of our rusted out front and rear fenders, and to reskin the driver’s door. Follow along as the sparks fly on our ’71 Nova.

Detroit Speed Mini-Tubs

While the tail-up ‘stinkbug’ stance was the way to get big rubber under a Nova back when our Chevy still had that new car smell, we want to be able to run our 18×11-inch Forgeline wheels and 275/40/18 tires and still keep the center of gravity low and the tires tucked neatly into the fenderwells. To do that, needed a mini-tub kit that was easy to install and Detroit Speed got the call since their tubs will fit wheels and tires up to 12 inches wide, making them perfect for our application.

Stamped from 18 gauge steel, these tubs are able to keep the stealth look plus have a perfect fit. “If someone who doesn’t really know what they are looking for glances into the trunk of a car with these tubs, they will have no clue that anything was changed,” said Stacey Tucker of Detroit Speed.

Included with the Mini-Tub kit is a great instructional DVD that walks you through the installation of the kit. The disk also contains files for the templates you will need to print out in order to assist you during the install.

The Mini-Tub Installation

In order to install the new tubs, the trunk interior and back seat need to be removed, along with the rear suspension, rear axle, and fuel tank. Because our ’71 Nova was already stripped down, we were able to head right into tearing the stock tubs out to make room for the Mini-Tub Kit.

First, we removed the deck lid braces and the seat back braces. We were extra careful during this step because we knew they’d be re-used with the new tubs. The seat back braces were simply cut off. Because the deck lid braces were spot welded on from the factory, we just drilled out the spot welds to remove them.


We carefully drilled out the factory spot welds and off came the deck lid braces, which will be reused with the new mini-tubs

Before the actual removal of the factory wheel tubs began, we took reference measurements, as recommended by Detroit Speed, from the tub to the outer wheel well. These measurement will be used later when we install our new tub kit. After three measurements were taken on each side, we cut out the wheel tubs carefully and slowly. We cut along the full length of the tubs and separated them from the rear of the trunk and floor pan.


We used a cutting wheel to remove the stock wheel tubs.

Once the old tub was out of the way, it was time to print out the templates that were on the DVD to guide us when notching the frame rails to fit the new tubs. “There is no need for any special paper or printer,” Tucker explained. “Just print them out on your home printer, and you are ready.”


After marking the frame rails using the printed templates, we notched them with the cutoff wheel.

“We use 1/8″ steel for the repair areas on the frame. That material is thicker than the original frame, and even though you notched it out, it will be stronger than before,” Tucker commented. We traced the template design onto our frame rail and began cutting each one out. After all of the cutting was done, we welded on our 1/8″ steel plates.


As you can see here on the driver’s side of our Nova, the steel plates go into place like pieces of a jigsaw puzzle. We tack welded them into position on the frame rail before fully welding them on.

With the body and frame prepared, it was finally time to fit our new wheel tubs in. We pushed them into place, made sure they were were we wanted them, clamped them down, and started marking dots on the lip of the tubs to keep them from warping when we did the finish welds.


We positioned the wheel tub where we wanted it and clamped it down before welding.

Once the new tubs were positioned exactly where we wanted them, the real welding began. We alternated the holes we were welding so we would get a nice, secure fit all the way around without overheating and warping the sheetmetal.


“Plug” welding gives a very strong bond between the new tubs and the factory sheetmetal, and is much easier to do properly than seam-welding the entire perimeter.

With these new wheel tubs in place, we will be able to run 18×11-inch Forgeline wheels and 275/40/18 tires, which never would have fit before the modification. Although these tubs did take a little while to install, it was not as difficult as it may seem. You can check out the full Mini-Tub Install photo gallery here.


Here’s the mini-tub fully installed, with the decklid support replaced and welded to the new sheetmetal. Once it’s prepped and painted, it will be hard to tell the difference from the stock trunk interior.

Working stiff

We really wanted to reinforce the frame on our Swinger Nova because it will be driven hard on the road and even harder on the autocross course. The subframe connectors from Detroit Speed will do just that by tying the front subframe to the rear frame rails. The design of these subframe connectors tucks them in underneath the car to maintain ground clearance, and they are meant to be completely welded in, both at the points where they connect to the subframes front and rear, but also all along the areas where they pass through the body. Seam-welding the subframe connectors in this manner greatly improves chassis stiffness by triangulating them into the entire structure of the car.


These Detroit Speed frame connectors are fabricated from 2″ x 3″ rectangular steel tubing and have milled slots that conform to the rear seat floor pan.

Easy Installation of the Subframe Connectors

For something with such a major impact on chassis stiffness, installing these frame connectors was a breeze. First, we made sure our frame was straight because we didn’t want to lock in any bend it might have had. “You should make sure your subframe is squared before any cutting or welding takes place,” recommended Tucker. Next, we traced the template onto the floorboard and cut it out to ensure the frame connectors would fit tightly.


Using the supplied template, we cut out the floor of the Nova to match where the subframe connectors would pass through.

The car was ready to get the connectors installed, but we needed to get the connectors themselves prepped. The square tubing is bent and TIG welded in a fixture by Detroit Speed for accuracy, but because every car is a little bit different from the factory, there are some brackets that need to be welded on each end to get the best possible fit. After welding the brackets on, we were ready to install the connectors. We welded the connectors onto the front sub frame and to the rear frame rails, and we were done!


With the connectors in place, we welded around the floorboard to tie the body and frame together and seal the floor.

Repairing the Door Skin, Front Fender, and Quarter Panel

The Swinger Nova came to us with a bit of a rust problem, but it was nothing too big that we couldn’t handle. This rust issue seemed to be confined to the driver’s side of the car, and we needed to repair the door skin, quarter panel, and front fender. Classic Industries hooked us up with everything we needed for this job, and the panels we received from them fit perfectly.

Repairing the Front Fender

The lower right section of the front fender was rusted all the way through and needed to be cut out. Classic Industries offers a factory-correct replacement for pretty much every piece of sheetmetal on this car, and because rust damage is pretty common on this area of the fender, they even provide patch panels to avoid the expense of replacing (and shipping!) the entire fender. The panel is stamped with the correct bend, and just needed to be trimmed to match the rusted area we cut out.


We tack welded the patch panel first, alternating sides in order to keep the heat down and avoid any warping. Once we were happy with the fit, we finish-welded the seam.

Removing and Replacing the Door Skin

Removal of the door skin was a breeze. All it entailed was grinding down the factory spot welds and separating the door skin from the door. Applying the new door skin, however, was a little more tricky.

We needed to make sure the skin was lined up just right in order for the door to match correctly with the fenders. With the door skin positioned where we wanted it, we clamped it to the door and threw on a couple of tackwelds to hold it down while we made sure the fit was good. We then finished up by carefully rolling the edges of the skin onto the door and installing the door onto the car.


The door skin was a perfect fit, so we clamped it down and carefully rounded the edges onto the door.

Replacing the Quarter Panel

This job was a piece of cake! We simply cut out the rusted part of the panel, removed it, and threw it away. In addition to complete quarter panels, Classic Industries also offers different partial sections to replace damaged areas while preserving as much factory sheetmetal as possible. In our case, the entire fenderwell needed replacement.


Most of the quarter panel was still healthy, so we trimmed and removed only the rusted fenderwell section.

Taking the same approach with this quarter panel as we did with the front fender, we carefully tack welded it in place, stitch-welded it once we were happy with the position, and then took a grinder to it to level out the welds and prepare it for body filler to completely smooth the seam.


The Classic Industries replacement panel is stamped to precisely match the contours of the factory quarter panel.

Firewall Fill Plate

Even though we are located in sunny Southern California where it can get pretty hot, we have no plans to put in an air conditioning system. With nothing running through the firewall, we decided to install a firewall plate from Detroit Speed. The plate is 18 gauge steel with a rolled edge and will cover up the holes that an air conditioning unit would usually run through. Now we’ll have a nice, smooth look to our firewall.


This firewall plate will add a nice, smooth look to our engine bay and seal off the otherwise-empty hole.

Things Yet to Come…

The engine that will power this ’71 Nova will be a GM LSA. If you’re wondering what the LSA is, it’s based off of the all-aluminum supercharged LS9 found in the current Corvette ZR1, detuned from 638 to ‘only’ 556 horsepower for use in the Cadillac CTS-V.

This engine is completely stock and the 1.9L supercharger is a little smaller than the 2.3L you would find on an LS9, with maximum boost pressure dropping from from 10.5 psi down to 9.0. We can’t wait to see what this supercharged LS engine will do to the Swinger Nova.


Factory spec for the Cadillac LSA is 556 horsepower at 6100 RPM, and 551 pound-feet at 3800.

Final Words

While we took our time to do the job right, the mini-tub kit was not as difficult to install as we originally thought it would be. Detroit Speed really hit the nail on the head when it came to getting the correct dimensions for a perfect fit. The same goes for their connectors. You can’t cut corners or rush a job like this, but Detroit Speed helped the process by providing parts that fit like they should and clear, easy-to-follow instructions

The ’71 Nova looks far better with all of the rust off and the new panels on. Even though we’ve already done a lot, there is still a bunch of work left to do, with the interior still gutted and the sheetmetal bare. Even so, we’ve got a great foundation with the LSA powerplant; pair that up with the amazing stopping power from the SSBC brakes and the impressive handling we’ll get from the Ridetech Street Pak Challenge kit, and this Nova is going to dominate the autocross course.

Article Sources

About the author

Paul Huizenga

After some close calls on the street in his late teens and early twenties, Paul Huizenga discovered organized drag racing and never looked back, becoming a SFI-Certified tech inspector and avid bracket racer. Formerly the editor of OverRev and Race Pages magazines, Huizenga set out on his own in 2009 to become a freelance writer and editor.
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