The ZL1: General Motors

The ZL1: General Motors’ First Ballot Hall of Famer

There is a valuable lesson we can learn about muscle cars from the NFL. 

Stay with me here. 

The National Football League is America’s unofficial national pastime (sorry baseball) and is enjoyed by millions upon millions every week of the season. We root for our favorite teams and players and talk all the trash in the world to our rivals.

But what sometimes gets lost watching football is the sheer astonishment we should feel by watching these gifted individuals do what they do best. The problem is that each week, we only see these physical freaks of nature competing against other physical freaks of nature. We don’t realize that the average by which we judge these athletes, the baseline we use for physical abilities, is outlandishly higher than what we would typically consider excellent.  

The baddest badge in GM history. (photo courtesy of Chevrolet Media)

If a few of those legendary players, like Randy Moss or, more recently, Tyreek Hill were lined up against you or me in a 40-yard dash, or we were given the assignment of trying to block JJ Watt or Aaron Donald, suddenly the true magnitude of their speed and strength would become painfully and embarrassingly apparent. It becomes very easy to forget that the 11 people we see on our team represent the absolute pinnacle of human performance in one way or another. But when we get firsthand experience of just how big, how fast, how strong, or how intense any of these monsters are, suddenly, a new level of respect can be attained.

This is exactly how it works in the world of sports and muscle cars.  

Each of us roots for a team — be it Chevrolet, Ford, or Dodge, the list goes on and on. But we follow our team and use their best players as the flagship for our loyalties. It becomes our best versus their best. And while it’s no new news that ‘racing improves the breed’, what it also does is dull our senses to just how incredible some of these magnificent machines were and are. Just as with NFL players, the problem is that we usually only compare these automotive phenoms to others that occupy the same rarified air. But when put into the context of everyday life, we can see why the NFL has a hall of fame and why there are museums dedicated to these superstar cars. And a clear first ballot hall of famer in the automotive world would undoubtedly be the Camaro ZL1. We want to give you a little perspective and context on what is easily the most freakishly fast RPO code in GM’s illustrious history.

As with so many of the wonders GM has graced us with from the 1960’s, the ZL1 was yet another creation from the famous speed-obsessed Zora Arkus Duntov. They were created to be a Ferrari killer much in the same vein as Carroll Shelby envisioned the legendary 427 Cobra to be. Outfitted almost identically as the world-beating L88 aluminum head engine, the ZL1 had one significant difference: instead of the iron block used with the L88, the ZL1 shaved off a full 100 pounds by using an aluminum block as well as aluminum heads. Four-bolt main caps and cast-iron sleeves were still employed in the essence of reinforced strength, though.

The Legend. (photo courtesy of Horsepower Memories)

From mild to wild, the ZL1 motor was a 427 on PEDs. (photo courtesy of Pinterest)

That massive weight reduction was then combined with a sky-high 12.5:1 compression ratio, race-ready mechanical solid-roller high-lift camshaft that measures 0.580-inch on the intake, and 0.620-inch on the exhaust values using 1.7:1 ratio rocker arms. Feeding this insatiable beast was a fire hydrant sized Holley double-pumper carb that earned its money by gushing 850-cfm of fuel through a high-rise open plenum intake. This engine would have definitely gotten the ‘Vette to pop for using performance-enhancing drugs, as it was rated at a very modest 430 horsepower, which was a half-truth at best. The ZL1 did produce 430 horsepower, but it also had a bit more. The question of peak power was never asked by the folks doing the rating, so while the ZL1 did make the advertised 430, it wasn’t done until its true peak of about 550-600 horsepower.

That hall of fame level power, combined with a lightweight, flared fiberglass body, the heavy-duty F41 suspension, Rock Crusher M22 close-ratio four-speed manual, and 3.70 rear gear synergistically combined to shred the Firestone Wide Oval tires. “Wide,” meaning 15-inch bias-ply tires, which on a car like the ZL1 is essentially outfitting superstar wide receivers Randy Moss or Calvin Johnson with penny loafers to wear on game day. With proper footing (drag slicks), the ZL1 has been clocked at 11.2-seconds at a staggering 127 mph. Switch over to slightly freer-flowing headers, and you have yourself a bonafide 10-second car right off the production line.

My team is faster than your team. The ZL1 was a legit 11-second monster. (photo courtesy of Corvsport.com)

The bad news here is that there were only three documented examples of the Ultimate Corvette ever created (as documented by LSX Magazine’s Rare Rides ). Sadly, after 1969, we never saw the ZL1 badge adorned on a Corvette again. However, the good news is that while the ZL1 Corvette was being produced concurrently, and in quite a bit more volume, there were also a few Camaro ZL1s that made their way into the league.

If Zora Arkus-Duntov were the Tom Brady of GM performance car builders, then guys like Don Yenko and Fred Gibb would have to be considered his Julian Edelman and Rob Gronkowski. If you don’t have people able to make the most of your talent, your true potential is hard to achieve. Yenko’s contribution to the game is well-documented, but Gibb doesn’t always get the credit he deserves. He was an Illinois-based Chevy dealer who understood the system. In a somewhat clandestine fashion that he may or may not have learned from Yenko, he used the covert Central Office Production Order (COPO) system to special order the most potent Camaro built to date.

The original ZL1 Camaro. An instant classic. (photo courtesy of Mecum.com)

The order came with the caveat that he needed to order at least 50 ZL1 Camaros to justify the build.  So that’s just what Gibb did, and fittingly, in total there were 69 total ZL1 in 1969.  Gibb ultimately ended up shipping 37 of them back to the company because it was a bit difficult to sell what was essentially a race car at double the sticker price thanks to the lofty $4,160 cost of the ZL1 option alone.

Much like the Vette, the ZL1 Camaro was essentially the second highest performance package that they then shoehorned in an even more juiced up motor.  Where the Vette used the L88, the ZL1 Camaro began life as a 427 COPO Camaro, which meant it was outfitted with either a a four-speed manual transmission or a Turbo Hydra-matic three speed automatic and then a 4.10:1 Positraction rear end, front disc brakes and a trick cowl-induction hood.  Although it weighed a couple hundred pounds more than the Corvette version, when given proper footwear, the Camaro ZL1 could manage a slightly slower 11.6 @ 122 mph at the track, though its hard to use the word “slower” when describing an 11 second production car.

The isn’t much to denote the ZL1 from the base car, until the light turns green. (photo courtesy of Mecum.com)

The ZL1 Camaro went into hibernation for more than 40 years. The badge did show up in 1971, then again in 1977, and made a third cameo appearance in 1999, but these were more specialized one-off cars that weren’t able to be ordered as actual customer cars. In 2012, while some were waiting for the end of the Mayan calendar to destroy us all, the ZL1 was resurrected and stormed on the track scene with one mission — to end the world of many Blue Oval guys around the globe.

5th Gen Camaro ZL1. The first ZL1 to grace the playing field in over 40 years. (photo courtesy of Chevrolet Media)

The 2012 ZL1 stepped back on the playing field with some serious new skills. Sure, before it could run in a straight line better than almost anyone. But the modern athlete, or supercar, needs to be able to turn and stop with exceptional ability and still be fast as hell. So, GM went to its bag of tricks and borrowed a 6.2-liter supercharged LSA V8 from the Cadillac CTS-V and combined that with a two-stage free-flowing exhaust to help the new ZL1 produce a ridiculous 580 horsepower and 556 lb-ft of torque. Backing that power was your choice of either a beefed-up Tremec TR-6060 MG9 six-speed manual transmission or Hydra-Matic 6L90 six-speed automatic. Helping all of that power stay useful is the Camaro’s new performance traction management system borrowed from the mighty ZR1. Five modes — a wet, dry, sport with and sport without stability control, and of course, race modes all serve their respective roles in different environments as needed.

 

Borrowed from the CTS-V, the LSA was a 580-hp supercharged beast. (photo courtesy of Chevrolet Media)

More than 30-percent of the ZL1’s parts were upgraded or explicitly changed for the Z. Most of those parts were to beef up what was once the Achilles’ heel of the Camaro — that being the suspension. A new generation of magnetorheological shocks (that can change damping 1000 times per second), strut tower brace, upgraded rear anti-roll bar, combined with an electrically assisted power steering unit (a first for the Camaro in any trim) helped the sticky track-ready Goodyear Eagle F1 SuperCar G:2 tires. With 285/35ZR-20 tires on the front and 305/35ZR-20’s on the rear, the car could navigate any curve that life or Laguna Seca could throw at it.  

The steering upgrade, combined with a very impressive weight distribution of 52/48-percent front/rear, made a very predictable car out of the corners. A cast-iron differential and stronger half shafts join forces with heavy-duty universal joints at the back of the vehicle. Also borrowed from the CTS-V were the ZL1’s calipers, though a two-piece rotor was used instead of the Caddy’s twin-disc setup.

The first ever ZL1 convertible. Feeling the wind through your hair is much different at 150 mph. (photo courtesy of Chevrolet Media)

All of these upgrades helped serve the ZL1’s ultimate purpose: to be one of the automotive performance elite. With such lofty expectations tied to the mythic ZL1 badge, we have to say, the reincarnation lived up to its namesake very well. Motor Trend tested a new ZL1 in 2012 and was able to run from 0-60 mph 3.8 seconds, 0-100 mph in just 8.7-seconds, and through the 1/4-mile in a scant 12.1-seconds at 117.4 mph, on it’s way to a top speed of 180 mph. Running around the skidpad, they attained a figure of 1.02 G’s and then, of course, scrub off all that speed back down from 60-0 mph in 108 feet. Some might scoff at those numbers, but keep in mind that these tests were with a completely stock car on stock tires, and let’s not forget that this is a 4,051-pound car. Fuel economy checks in at a paltry 14/19 city/highway, but no one is buying a ZL1 because they need an eco-friendly commuter car.

More than just a drag racer, the modern ZL1 relished being thrown a curve or two. (photo courtesy of Chevrolet Media)

Ending its run in 2015, the fifth-gen Camaro ZL1 took a two-year hiatus, handing the spotlight over to Camaro’s newest generation to take center stage. This is standard GM operating procedure for high-performance trims, to first allow for the new sixth-gen Camaro sales rack up for the base models, and second, to make sure all the bugs are worked out before turning up the performance volume to max. The sixth-gen debuted in 2016, and then in 2017, the ZL1 made its triumphant return, and was more than worth the wait. Combined with the newly available 1LE package available as of 2018, we highlighted a few months back (link), the new ZL1 went from a Pro Bowl-caliber player to All-Pro with one change in uniform.

The 6th Gen ZL1. Combined with the 1LE package, is easily the greatest Camaro ever assembled. (photo courtesy of Chevrolet Media)

 

The sixth-gen ZL1 is based off of GM’s new Alpha Platform, which shaves off 300 pounds compared to its predecessor. In 1LE trim, which has its own history, it sheds another 75-pounds off of that for a total of 3,837. That weight savings might not seem impressive, but combined with the upgraded motor, suddenly, the power-to-weight ratio of the ZL1 somehow got even more impressive than it already was.

Power in the sixth-gen comes from the C7 ZO6 in the form of a 6.2-liter supercharged and intercooled LT4 V8 that offers up a superheroic 650 horsepower and 650 lb-ft of torque. In 1LE trim, the only available transmission is the Tremec MH3 six-speed manual, as it weighs 14-pounds less than the automatic. But opt-out of 1LE form, and you can have your all-star team-level Camaro with a Hydra-Matic 10-speed auto. That power then gets routed to the rear wheels, naturally, via an electronic limited-slip differential sporting a 3.73:1 rear gear.

The mighty LT4. Half engine, half amazing. (photo courtesy of Chevrolet Media)

 

Up front, a massive splitter and colossal air ducts help feed the 11 different heat exchangers located around the car to help mitigate high temperatures that can be seen on a track day. And this car is absolutely built for the track, not just the dragstrip. The carried-over performance traction management system gets tweaked, and new multimatic dynamic suspension spool valve dampers to play with. Those dampers are hard-mounted to the car’s body instead of using traditional (and prone to failing) rubber bushings. To further convey that the ZL1 was not created for posers, you can also customize your front ride height, rear stabilizer bar, and camber plates manually to suit your driving style. Oh, and that massive curved rear wing? Unlike your minor-league garden variety rodded-up Honda Civic, the ZL1 wing producers up to 300 pounds of downforce at 155 miles per hour, which the ZL1 can hit with more ease than Tom Brady running the 40-yard dash.

 

With experience comes knowledge, and GM could not let all that power be made for naught. More important than how much power your engine makes is how much it puts to the ground. GM went to work and employed some old friends to create its first racetrack rubber. Tires for the ZL1 are DOT-approved R-compound Goodyear Eagle F1 SuperCar R3 rubber that measure a steam-roller-like 305/30/ZR19 up front and a ridiculous 325/30ZR19 out back. Six-piston Brembo brakes clamp down massive 15.35-inch rotors up front, and 14.4-inch four-piston units in the rear join forces to stop speed like Ray Lewis tackling an unsuspecting running back.

So what is the result of sending an already stout car back to the gym to get even stronger? Well, Car and Driver tested the ZL1 1LE and ran the 0-60 mph test in 3.4-seconds, 0-100 mph in just 7.4-seconds, on its way to a 1/4-mile time of 11.4-seconds at 124 mph. Even 0-150 mph took just 19.2-seconds with a top speed of 190 mph. Braking from 60-0 mph took just 96 feet. For context, it wasn’t too long ago that sub-100 foot scores were unattainable. Around the skidpad, the ZL1 posts an internal-organ shifting 1.17 G’s, and even with the extra 70-horsepower versus the fifth-gen ZL1, the sixth-gen manages to improve fuel economy to 13/21 city/highway mpg.

At 155 mph, the ZL1’s rear wing creates 300 pounds of downforce. (photo courtesy of Chevrolet Media)

 

There’s no doubt that the ZL1, in any generation, is a first-ballot automotive hall of fame inductee. Much like professional football players, we may lose sight of just how impressive a car like this can be because all we see it compared against are cars like the GT500, Hellcat, any number of Ferraris or Porsches, which are all pro-level speedsters in their own right. Both athletes and performance cars are all playing on such a high level, with what could be considered superhuman abilities compared to your average layperson (or lay-car), that we never stop to realize how otherworldly they are. But jump out of the stands and onto the field at an NFL stadium (which is not a good idea, by the way) and you will see just how much bigger, faster, and stronger those gladiators are on the gridiron. The same notion applies if you were to get out of your 2010 Camry and settle into a 650-horsepower street-legal race car –suddenly you will have a very real understanding and much better perspective of just how special the ZL1 badge is.

 

The modern rendition of of the ZL1 emblem commands just as much respect as the original. (photo courtesy of Chevrolet Media)

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