Ever since Mopar released its Hellcat V-8 as a crate engine last year, Ram enthusiasts have considered the possibility of another supertruck that could revive the performance passions the iconic SRT-10 models produced from 2004 to 2006. If you remember, those regular-cab models came with a 500hp, 8.3L, all-aluminum Viper V-10 engine and six-speed manual transmission. Ram also released a Quad Cab version with an automatic transmission. Both models were street brutes with more than 500 lb-ft of torque available through much of the power band. However, with a Hellcat under the hood, more than 500 lb-ft of torque would available at the rear wheels—not just the flywheel!
Rated at 707 hp and 650 lb-ft peak torque, the 6.2L supercharged Hellcat engine has all the tools to create another uber-performance street truck, if you know how to drop one in a late-model platform. Dakota Customs, located near Rapid City, South Dakota, specializes in Hemi conversions and has swapped numerous Hellcat engines into Jeeps. But this was the shop’s first Ram project, which presented its own set of challenges.
“Getting the engine to run wasn’t a big problem, but there were specific calibrations that had to be addressed,” shop manager Dan McKeag says. “For example, the torque management program for the transmission shifts. There are cooling fan differences, ABS brake differences, and more.”
Physically, there were few issues when it came to replacing the stock 5.7L Hemi with the Hellcat. The team retained the stock eight-speed automatic transmission, flexplate, and torque converter. This swap was performed on a four-wheel-drive truck, although it would be just as uncomplicated with a rear-wheel-drive model. Grinding was needed to clear the alternator, and a little surgery was needed on the firewall to make room for the intercooler fluid lines.
| A 707hp Hellcat V-8 engine stands ready to be swapped into a new Ram pickup.
The key to mating the Hellcat with the Ram is the wiring harness. Dakota Customs used a Hellcat PCM and fused the stock wiring harness with a Hellcat automatic harness. The team basically laid out the two harnesses, noted the differences, and consulted wiring diagrams to make sure the correct pin connectors were utilized.
Once the Hellcat engine was swapped in place, the PCM could be unlocked and recalibrated with the necessary information that keeps both the truck and the engine happy. For example, the Hellcat requires a multi-phase fuel pump to keep up with the supercharger demands. Dakota Customs couldn’t use the stock Ram pump, so the crew swapped in an Aeromotive dual fuel pump and regulator. Also, the Ram comes with an engine-driven fan, but Dakota Customs wanted an electric fan to address cooling issues. The crew found one from an older Ram V-6 pickup and calibrated the PCM to operate it accordingly.
The swap almost doubled the horsepower and torque produced by the factory 5.7L Hemi. In addition to the performance upgrade, Dakota Customs added bold SRT Hellcat graphics and a more aggressive wheel-and-tire combo, with 35-inch Toyo tires wrapped around 22-inch SRT replica wheels. With these looks and power, there was only one more thing to do—think of a name. The Ram Cat? The Hell Ram? The Rebel Hell? The possibilities are endless.
| With a stock 5.7L Hemi, the Ram 1500 made 300 hp on a chassis dyno, with peak torque of 323 lb-ft. Readings were measured at the wheels.
| Here’s the factory engine bay. Relocating the airbox, modifying the wiring harness, and recalibrating the PCM will be crucial to a successful swap.
| Access to the engine is easier after the front bumper, radiator, and core support are removed.
| There are around 100 connections on the wiring harness, including hard-to-reach locations on the underside. The fuel lines are also disconnected and removed at this time.
| The exhaust system is disconnected, the torque converter is unbolted from the flexplate, and the engine-mount bolts are removed. It helps to have a wide variety of extensions and specialty tools to reach some of the hardware.
| There’s plenty of room in the bay, so the factory Hemi slides out rather quickly.
| Basically, Dakota Customs blends a Hellcat harness into the stock harness. Both are laid out on a table and compared. The necessary Hellcat connections are then integrated into the factory harness.
| For example, the Hellcat harness has four MAP sensors, compared to one for the 5.7L. So, those wires are added and hooked into the appropriate cavities in the PCM connector.
| Here’s another wiring difference. Note the different position of the coil packs on the valve covers. The Hellcat requires longer wires on the harness. Also, the Hellcat uses separate wiring for the coils and fuel injectors. Normally, they’re taped together.
| The truck needs a rear-sump pan (black pan, far left in photo), but the standard oil pan for the Hellcat Challenger has a front-sump location (far right). For this application, Dakota Customs uses a pan from a ’10 5.7L Grand Cherokee (center).
| Here’s a comparison of the Grand Cherokee pan (left) and the stock Ram pan with a separate reinforcement needed to bolt up to the transmission.
| With the rear sump pan, a longer pickup was needed (top). It’s compared to the factory Hellcat pickup (lower).
| On the Hellcat, the dipstick goes directly into pan. The Hellcat block has a provision for a standard dispstick tube, but the plug has to be knocked out.
| Dakota Customs wanted to use the Hellcat torque converter found in the HP90 transmission (left), but it wouldn’t fit in the bellhousing of the Ram transmission. So, the stock torque converter (right) was used.
| The stock 5.7L flexplate was retained, but it needed a spacer sleeve to support the snout of the torque converter.
| There were no immediate clearance issues when it came to dropping in the Hellcat long-block, with the exception of the oil filler housing. Note that the supercharger and intake were removed to facilitate the installation.
| Here’s the Hellcat long block in place. The Dakota Customs crew then sized up the length of coolant lines and lining up the pulleys to mount the accessories. They also took a look at exhaust options, finally settling on the exhaust manifolds from a 2010 SRT Grand Cherokee.
| Here’s a view from below. Note the rear-sump oil pan and the stock Ram eight-speed transmission. The Cherokee exhaust manifolds have also been installed.
| The oil filler housing was moved from the driver side to the passenger side because of clearance issues with the brake booster. The plug was then moved to the left side of the engine.
| Some grinding on the front edge of the motor-mount bracket was needed to clear the alternator.
| Here’s the alternator being mocked up to check clearance and alignment with the pulleys.
| Dakota Customs retained the truck’s stock fuel tank but upgraded to an Aeromotive Dual Phantom fuel pump. It features an adjustable mount for the fuel-level sending unit (see arrow). The locating tab on the support rim around the mounting hole was removed to allow the new fuel pump to settle into place and be secured to the tank.
| The dual pump requires two feed lines. Both lead to a Y-block mounted just before the fuel filter, which is mounted on a framerail. A single line then flows up to the regulator.
| The Aeromotive regulator is mounted on the firewall, and a return line is fed back to the fuel tank. It’s set at 60 psi.
| The harness was built on the table, and the crew begins hooking up the sensors and other connections.
| The firewall had to be clearanced slightly to make room for the supercharger coolant hoses. There was nothing behind the firewall, so it was cut out and an appropriate patch with insulation filled up the hole. The Hellcat supercharger does have a standalone intercooler system. The reservoir was mounted on the passenger side of the engine bay, and the pump was mounted in front of and below the reservoir to always stay primed and avoid any cavitation issues.
| Here’s another view of the supercharger and accessories in place.
| The core support, radiator, and front end are returned to the truck so the coolant system can be hooked up.
| Dakota Customs needed to leave the battery and fuse box in the stock location, which blocked a convenient solution for fabricating an air inlet box. But the crew solved a plumbing problem by combining two upper hoses from a Grand Cherokee and splicing in a heater-hose connection. The stock lower hose worked just fine.
| The air inlet problem was solved by locating an open-element filter as low and forward as possible, using pipes from an earlier project that involved a 4.0L Whipple supercharger.
| Here’s the finished engine bay. The exhaust included MagnaFlow 3-inch catalytic converters and a basic MagnaFlow cat-back muffler and dual-outlet tailpipe system.
| The Hellcat PCM had to be unlocked and retuned with help from HemiTuner Performance.
| The final dyno test revealed 577 rear-wheel horsepower at 5,400 rpm with peak torque of 540 lb-ft at 4,150 rpm.
| The Ram was treated to bold SRT graphics and 22x10 Replica SRT 10 wheels wrapped in 35x12.50-22 Toyo AT Open Country tires.