You can probably tell we plan to go pretty fast in our '63 Nova hardtop project by the extensive rollcage you see in this story's lead image. When you last read about our latest street/strip project we were fitting our Flex-a-lite fan and radiator combo between the 'rails; in this installment we completely upgrade the chassis with a Chris Alston's Chassisworks kit (PN 7021), as well as some of their optional upgrades in order to keep us safe if something tragic happens during dragstrip runs. But safety wasn't the only reason to put an 8.50 quarter-mile–certified rollcage in the stock-but-worn X-body, chassis flex from hard launching a little old car was also a concern. You may remember in the first story in this build ("Master Blaster," Dec. '12 issue, page 36) we stripped the '63 to bare metal in search of cancer or any detrimental body damage. Well, we didn't find any major exterior damage, so we were pleased, but what we didn't see with the soda blast was the superthin '60s sheetmetal that had our bodyman cursing the car every time he'd put a grinder to agitate an area for Bondo work. The slightest pressure and the abrasive disc would punch through, meaning the car was even more of a "potato chip" than we thought. We decided to install a 'cage that would not only protect us in a crash, but also ensure that our fire-breathing small-block we have planned won't twist the six-cylinder two-door. Another thing we considered about the lean and blasted body panels was the weight we were saving by not having four coats of paint and primer. The goal with this street-legal project car is to build it is as light as possible, while being safe and structurally sound. Thanks to a chassis parts supplier with decades of experience and a skilled fabricator with the knowledge of the NHRA rulebook, our vision for this car is a step closer to becoming reality.
We contacted Casey Steinman at Overkill Fabrications in Upland, California, for the installation of the Chassisworks 'cage kit (as well as few other upgrades) to prepare the car for the SBC/TH400 powertrain. On the to-do list for the primered hardtop included deleting the back seat and designing and NHRA-legal bulkhead that keeps flames, smoke, and fumes away from the driver; fastening the Harwood fiberglass cowl-induction hood (PN 5750) and trunk lid (PN1067) down using Dzus fasteners, and installing a pair of subframe connectors from Chevy 2 Only (PN 2000). Since the early Novas have a subframe (making the body more of a structural part of the car when uncaged), the guys at Chevy 2 Only designed some mild steel connectors that make the Nova have a fully connected chassis. This also gave Steinman something to tie the whole 'cage into the stock frame, essentially.
In keeping with the lighter-faster-stronger theme, we opted for Chris Alston's chrome-moly 'cage kit instead of mild steel for a few reasons; the weight savings (see sidebar Bar Thickness and Diameter), and it also will allow us to upgrade to an SFI cert that will allow the car to run as quick as 7.50 in the quarter-mile. While we plan on competing in a street-legal NMCA class, we envision this car becoming an even quicker animal. Coincidentally, some may say this 'cage is "overkill", but we built it with even higher speeds in mind. In other words, this car is only destined for the street for so long. That's why we also ordered Chris Alston's Funny Car addition (PN 7227). If you want to see Alston's ultimate drag race 'cage for a door car, check out the sidebar on Editor Henry D's third-gen Z28, Project True 10.5, that he plans to run over 200 mph.
So, you want to go fast without dying? Read this article to find out what we did to make our Nova project structurally sound.
1. Bar Thickness and Diameter: When it comes to rollcages, the bar diameters and thickness vary depending on the material you choose. For mild steel 'cages, fabricators use 13/4-inch diameter, 0.134-inch wall tubing (on right), which is the heavier option. Chrome-moly 'cages use a lighter 15/8-inch diameter, 0.083-inch wall tube (on left), but are more expensive and cost more to install. Other sizes are also used in further upgrades, such as Funny Car hoops and gussets, and typically measure 11/4 in chrome-moly. The idea is to increase the overall rigidity of the 'cage in critical areas. One thing to consider when choosing material is how soft it is; chrome-moly is more rigid, but mild steel is considered a soft metal.
2. Here is an example of a basic Chassisworks steel four-point rollbar kit (PN 7000). This will allow you to run no quicker than 11.49 in the quarter-mile.
3. The eight-point kit (PN 7001) is also a mild steel 'cage kit with the added bars SFI requires to run 10.00 in the quarter-mile. Both the 7000 and 7001 can be MIG welded in.
4. While there are many variations to the rollcage kits Chassisworks offers, this is an example of a rollcage that can be certified to run up to 8.50 in the quarter-mile. The one pictured is available in mild steel (PN 7003) and chrome-moly (PN 7021). All of these kits come via UPS in boxes filled with metal raw bars and need to be fitted.
5. Fitting the main hoop and some of the crucial bars in the 8.50 cert design is the first step to the 'cage installation process.
6. Here, Steinman welds in the steel floor plates that come with the Alston 'cage into place. Keep in mind these only connect to the sheetmetal floor to the main hoop behind the seat and don't tie into the frame; however, it's not required to do so per NHRA guidelines.
7. As you can see, without the subframe connectors, the early Novas have a leaf-spring mount that looks largely unsupported. These tubular connectors enforce this critical suspension attachment point, while connecting the frame.
8. The bars that extend to the rear actually line up over the frame and didn't need to be triangulated like the main hoop in this build.
9. This shot shows the Chevy 2 Only subframe connectors and driveshaft hoop/crossmember we had welded in by Overkill.
10. We opted for crossbraces in the doors. This was done with the intention to make this car legal for quicker dragstrip times.
11. To further strengthen the cage, Steinman also made some kickers that extend from the front floor plate to the factory Nova frame. Triangulation like this works by simple physics: It dissipates impact into a larger surface.
12. Another added option we went with was a crossbar behind the main hoop—convenient for if and when we decide to upgrade.
13. This junction behind shows all the bars join the main hoop; this will be behind the driver seat.
14. With the 'cage all TIG welded and tied into the upgraded frame, we painted the bars satin black with Dupli-Color engine paint. The final step will be getting a literal seal of approval from an NHRA tech that we'll have to show off at a later date. Look for the following article in this build where we put a shiny coat of DuPont's Redline Red on the Hellion's exterior, then it's time for that fire-breather we wrote about earlier.
Project True 10.5
Several years ago we started dreaming up a third-gen Camaro to compete in the True 10.5 class, a class reserved for both stock suspension and back-halved cars like ours, but one that also requires competitors to retain the factory firewall. Up front, aftermarket suspension is allowed, however it must bolt into the factory location as well. Since then, we ended up purchasing a '91 Z28 that we completely tore apart, and delivered to Bill Hickok of Hickok Race Cars in California City, California, where he's been assembling and fabricating the 25.2 chassis. In past issues, we've shown you the Chris Alston's Chassisworks FAB9 rearend build and install. This time around, we wanted to showcase the basics of a 'cage install with the '63, all the while updating you on the '91 Z28 chassis. We're proud to say that Bill has been keeping his welder busy in order to meet NHRA's strict chassis certification requirements and it's only a matter of time before we get our dedicated track machine onto the tarmac. —Henry D
1. If you're looking to build a third-gen like ours, Chris Alston's Chassisworks offers a complete kit to transform your chassis into a 25.2 roller. Per NHRA requirements, the chrome-moly tubes feature a 15/8-inch diameter and 0.083-inch wall thickness.
2. Compared to the 8.50-certified 'cage, the 25.2 is a lot more elaborate and requires the entire floor to be removed for the lower bars and trans tunnel. This is a single-rail design that'll eventually be covered with aluminum floors; however, we're placing steel floors underneath the driver seat to meet certification requirements. It's also good for wear and tear.
3. Our Chassisworks antiroll bar is a tubular spline piece featuring a 1.25x0.188-inch wall with steel endlink tubes.
4. The lower main crossbar connects the rear four-link.
5. Out back, the rear tree is a critical component to the chassis structure by housing the mounts for the shocks and the antiroll bar, and it also supports the chassis side four-link brackets. This area alone is what can make or break a chassis from being stable on the big end and producing consistent repeatable performance numbers on the track.