Now the facts can be revealed about the most recent buildup of our 1968 Charger known as the General Mayhem. Over the past several months we’ve had an Interweb jab-fest with Richard Rawlings and Gas Monkey Garage that led up to an 1/8-mile heads-up showdown of 707-horsepower, Hellcat-powered cars at our Roadkill Nights event on August 12, 2015. We got our doors blown off. They brought a lightweight, back-half ’67 Dart with a Powerglide and a trans brake, while we stuck to the rules we’d set: 3,500 pound minimum, leaf springs, 12-inch tires, and a 2015 Dodge Hellcat engine and trans. Up until now, that’s all you’ve really known, as we’ve been kind of secretive about our prep for the Gas Monkey drag race. Now we’re going to spell it out. If you don’t want to read all the details, scroll to the bottom for the spec list on the General Mayhem.
First, if you’re new here, the General Mayhem is a ’68 Charger that we traded for a set of cylinder heads a few years ago. Next, we bought a class A motorhome, tore the 440 out of it, threw in some leftovers from our ’73 Fury race car (for 24 Hours of Lemons) and went rally racing, Dukes style. More recently, we yanked the drivetrain out of the General and heaved it into the Crop Duster, our ’70 Plymouth street/strip car. There was a new plan for the General Mayhem: Dodge had become our title sponsor, so we scammed a 2015 SRT Hellcat drivetrain out of them. That drivetrain happened to be attached to a complete 2015 SRT Charger development car that was destined for the crusher. The swap was on.
We sent both the General and the donor car to Diversified Creations (DiversifiedCreations.com) in Brighton, Michigan. Our buddy Mike Copeland runs the place, and is the go-to guy for making magic happen with engine swaps involving new Detroit technology. The plan was to slap the Hellcat drivetrain into the car, then drive it cross-country from Michigan, through the Black Hills and Yellowstone, arriving in Washington for a return visit to the Dirt Fish rally school where we’d run the Charger in ROADKILL episode 32. Around the same time that the Hellcat engine was mounted in the General’s engine bay, we noticed that both ROADKILL and Gas Monkey Garage were sponsored by Dodge, and because of the connection, we issued a challenge for the GMG guys that had been outlined by Roadkill Nationer Jeremy Nutt: “Who can build the better junkyard car in 3 days and drive it 1,000 miles? No TV magic, just gearheads.” Gas Monkey ignored it, which is understandable. However, Dodge contacted Rawlings, who agreed to a Hellcat-powered showdown as Gas Monkey was also building a car. The Internet smack-talk was on. Simultaneously, our company (TEN: The Enthusiast Network) had been working on the Roadkill Nights event, an 1/8-mile drag race in the parking lot of the Silverdome in Pontiac, Michigan. The plan for the General Mayhem changed to support the event. It was going to become a drag car. Even with the car’s purpose flipping to straightline performance, we wanted to make sure that everything could be changed back to our original Mad Max/General Lee, off-roady kinda vibe.
Nearly a year ago, in our first talk with Dodge president Tim Kuniskis, we told him we wanted to execute the very first swap of a Hellcat into an old muscle car. He quipped, “I don’t think you’d ever be able to make it run,” referring to the challenge of the new, complex, multi-tiered electrical system in the production car where there are multiple computers that all need to talk to each other: one each for the engine, trans, body, and other accessories. Copeland and Diversified knew that this was the case, and had a simple plan to overcome the problem for our short deadline: swap the entire electrical system from the ’15 into the ’68.
Daryl DeLaere runs the shop at Diversified and is about the fastest, most relentless wrench we’ve ever seen. With Daryl, his crew, and us, the 2015 donor car came apart in half a day, and the engine and trans were in place the next day. That’s when we left, and by the time we returned three weeks later, the car was a driver. We told him to do it “ROADKILL style,” which meant zip-ties, tex screws, and no detail painting were fine. It saved time.
The physical mounting of the engine required a large notch in the stock K-member, and the factory mounts had to be cut off so that custom solid units could be fabricated. The trans tunnel needed a few cuts to clear the huge ZG eight-speed Torqueflite automatic transmission, including trimming and reinforcing the factory torsion-bar crossmember. The eight-speed auto uses an unusual CV-joint output shaft and a solid driveshaft with no slipyoke, because the 2015 Charger has an IRS. As a solution, the ’68 Charger got a custom center carrier bearing setup, using a short section of the 2015 Charger driveshaft coming out of the trans, then into a Ford F250 carrier bearing, and then into a custom shaft to the rearend including a slipyoke.
The headers are Pacesetter 1-5/8-tube units for a Chrysler 300 with a 5.7L Hemi. They fit the passenger side just by mounting them on the head and then heating them with a torch and bending them to clear the frame and torsion bar (remember, we approved ROADKILL build techniques). The driver side header needed a couple tubes fabricated. It was tight on that side because we retained our Borgeson power steering box despite the weight penalty. The box is connected to the original Hellcat pump with custom hoses. While the power steering pump was left in place, the air-conditioning compressor was ditched.
All of the 2015 Charger’s cooling system was installed in the Mayhem, including the radiator, trans cooler, and intercoolers for the supercharger. The only thing omitted was the factory oil cooler. It took some holes and cuts to the stock ’68 core support to get all that junk mounted. The 2015’s puke tank, intercooler tank and pump, power center, and other underhood accessories were all mounted in the older car’s engine bay.
Next, we get into the electronics. The first step was messing around with the 2015 Charger before it was taken apart, disconnecting various devices to see what would and would not work. For example, the wheel-speed sensors can be disconnected and the car will operate perfectly, though you get a warning light and none of the traction or stability controls will function. It kills the speedo, too. But while wheel sensors can be unplugged, the car won’t run at all if you unplug the ABS controller. Therefore, the ABS unit is mounted into the General Mayhem and plugged in, even though it’s not doing anything.
The car also carries the engine, body, and trans computers (the latter is inside the transmission) well as a number of smaller control modules. As a result, the Mayhem now has a 2015 steering column and wheel, a 2015 instrument cluster, and even a touchscreen setup. Most of the luxury features are gone, but the screen still controls the performance functions, like the transmission modes. Even the 2015 fuel tank and all its evap systems are in place, mounted in the trunk and sealed off from the driver compartment. The 2015 brake-pedal assembly had to be used, as well.
With all the 2015 stuff in place, the car fired right up the first time, and the engine and trans functions like a stocker. But what about traction for that 707 horsepower and 650 lb-ft of torque? We didn’t want to tear up the General Mayhem with too many mods, but considering we had to race in a parking lot, we thought we’d need a lot of tire and cringed as the stock, rust-free wheel tubs were cut out to be replaced with aftermarket steel tubs to fit our 31×13.50-15 Hoosier QuickTime Pro, DOT-legal tires on Billet Specialties Street Lite beadlock wheels. The leaf-spring mounts were moved inboard, and we bought CalTracs leaf springs with 22-inch front segments like the stockers (the Mopar Super Stock springs that have been used since the ’60s have shorter, 20-inch front segments and in our experience they ride porly). The springs were augmented with CalTracs bars and QA1 double-adjustable billet shocks. The front suspension remains totally stock aside from more QA1 shocks and QA1 strut rods. The antiroll bars were removed from both ends of the car.
For the rearend, we really wanted to keep the Mopar 8-3/4, but we knew we would potentially need more strength, but more realistically, our short testing deadline demanded that we be able to change gear ratios at a moment’s notice, and its much easier to find Ford 9-inch gears and carriers than Mopar stuff. Miraculously, Moser Engineering cranked out a complete custom rear axle assembly for us in five hours—with us calling in favors, of course. The Moser 9-inch has 35-spline axles (stronger than the stock 28- or 31-spline) and an aluminum spool. Initially, we ran a 4.11 ring and pinion.
Yeah, Diversified also installed an NOS Fogger and progressive nitrous controller. The Fogger was on the engine very early in the game, but we kept it a secret. Keyboard commandos have claimed that we added the juice in a last-second panic before the race with Gas Monkey, but we had it on the car all along.
With the car completed in mid July 2015, we had to have had the world’s first running and driving swap of a Hellcat drivetrain into an older car. We know the Gas Monkey project was not running at that point, but we were ready for drag strip testing. But we already had one bit of bad news: with all steel body panels, the big trans, and the rollcage, our ’68 Charger weighed 3,880 pounds with the driver. And that’s with a totally gutted interior and no window glass aside from the windshield. The car is a tank.
Our first stop was Milan Dragway in Michigan, where we’d asked for zero track prep because we know we’d be dealing with poor conditions at the Silverdome parking lot race location. Initially, the car was porpoising off the line fairly badly, but fine tuning the compression and rebound settings on the QA1 shocks proved miraculous. We also played with rear tire pressure, settling on 9 psi cold. The CalTracs bars were set at ¾-turn of preload on both sides. With this setup, the Charger would just barely lift both front tires off the ground on launch. Our best pass of the day showed a 1.7-second 60-foot time, 7.10 at 99 mph at the eighth, and 11.07 at 122 in the quarter. That’s all without nitrous.
Next, we drove the car on the highway 140 miles—just to prove we could—to US 131 Motorsports Park, where we also asked for more prep. We got nearly identical performance results, with slight improvements with more fine tuning of the shocks. We had even more gains from changing the transmission into Track mode, and it shifted more quickly, reducing time on the rev limiter. One of the things we’ve found with all the new Hellcats is that they rpm so quickly that they tag the factory rev limiter between shifts, especially with tires spinning, and the Mayhem setup was no different. Track mode improved it. Lastly, we swapped the 4.11 cogs out of the Moser rearend and threw in some 3.70s. This required some more shock adjustments (we can’t tell you how happy we are with those double-adjustable units), but gave us the car’s quickest times yet: 1.66-second to the 60-foot mark, 7.02 at 101 at the eighth mile, and 10.90 at 125.24 at the quarter. It was a 10-second car with bone stock drivetrain—no nitrous! You might say, “I’ve seen bone stock Hellcats run 10.90s on drag radials, and they weigh much more!” You’re right, but you have to account for weather and track conditions. We had a stock 2015 Hellcat Charger with us at US 131, and it ran at the exact same time as General Mayhem, so it’s a good A/B comparo. The 2015 went 1.72 to the 60, 7.44 at 95.56 at the eighth, and 11.49 at 121.2 in the quarter. We also weighed the cars on the same scale: the 2015 was 4,710 without driver, and the Mayem was 3,700 without driver.
As we write this, we’ve never run on a real drag strip with the nitrous. Nope, we test-fired it a few times at a discrete off-track locale just to make sure it wouldn’t shut off the engine or explode the blower off the car, and then we headed to our showdown with Richard Rawlings and Gas Monkey Garage at our own Roadkill Nights event at the Silverdome in Pontiac, Michigan.
Of course you know we got beat, solidly. There are reasons for that, and don’t read them as excuses. Richard Rawlings had posted videos claiming he needed us to make any rules we wanted. We did, and he ignored all of them. The Gas Monkey ’67 Dart had a fabricated chassis from the firewall back, a four-link drag suspension, an all-aluminum interior, and a Chevy Powerglide racing transmission with a trans brake and a 9-inch torque converter. To counter our nitrous, the Gas Monkey Hellcat was running on E85 with a larger crank pulley for more supercharger boost and a tune that’s known to make about 800 horsepower. We could have done all that, except for the problem of time, money, and—most of all—we just didn’t want to hack up our car that badly. We stayed true to our original rules outline and counted on Gas Monkey never getting their car running. They did, but just three days before the race with the help from Diablo Sport techs who figured out how to get their Hellcat to run stand-alone without the other computers on board (except, we suspect, the body computer). Aaron Kaufman and the Gas Monkey crew did a great job dialing in the car in a single day at Yello Belly drag strip in Texas, showed up at Roadkill Nights, and laid it down hard. Their car is legitimately fast, outrunning us by a car length and a half even after we tree’d Aaron. We didn’t feed enough nitrous to it to overcome an 800 to 1,000-pound weight disadvantage, a racing Powerglide with a high-stall converter, and a four-link suspension. Even so, it was a great race at an amazing event in front of almost 10,000 people. Both the General Mayhem and the Gas Monkey Dart lifted tires and made their best passes ever on a temporary drag strip in an abandoned parking lot with so many whoopdeedoos that it’s a miracle that neither one of us had to lift off the throttle. It was a thrill ride, for sure.
What’s next for the General Mayhem Charger? First, we want to go to a real track and try it all-out with the nitrous. It’d be neat if we could spray it into the 9s. After that, the rear taillights must be swapped back to the original ’68 Charger units (wiring challenges with the 2015 harness left us with the 2015 lights on the back for now), and then we want to take it back to rally/handling trim. Dirt Fish awaits, and we wanna greet it with 707 horsepowers.
THE GENERAL MAYHEM
What: 1968 Dodge Charger
Weight: 3,880 with driver
Engine: Stock 2015 Dodge SRT Hellcat, 6.2L, supercharged, 707 hp and 650 lb-ft. Boosted with NOS Fogger nitrous oxide injection with 250hp jetting
Transmission: 2015 Dodge SRT eight-speed Torqueflite automatic
Rear Axle: Moser Engineering 9-inch with 35-spline axles, spool, 3.70 gears
Front Suspension: Stock with QA1 double-adjustable shocks and QA1 strut rods
Rear Suspension: CalTracs leaf springs, CalTracs traction devices, QA1 double-adjustable shocks, leaf springs moved inboard to the framerails, wheel tubs
Wheels & Tires: Billet Specialties 15×4 and 15×12 Street Lites with rear beadlocks. Hoosier 31×13.50-15 QuickTime Pro DOT tires on the rear and Hoosier 27×4.50-15 drag fronts.
Best Pass: With no nitrous, 1.66-second to the 60-foot mark, 7.02 at 101 at the eighth mile, and 10.90 at 125.24 at the quarter. As of this writing, the car has not been timed with nitrous oxide. As a point of reference, we ran our totally stock 2015 Dodge SRT Charger Hellcat on drag radials at the same time, and went 1.72 to the 60, 7.44 at 95.56 at the eighth, and 11.49 at 121.2 in the quarter.