Complete Build Guide for a 750+ Hp Dodge Challenger 6.2 Hellcat with Forced Induction and Supporting Mods

Understanding the Hellcat Engine’s Potential

The Dodge Challenger 6.2 Hellcat is already a formidable machine, delivering 707 horsepower and 650 lb-ft of torque from its supercharged 3.6-liter HEMI V8. But the engine’s forged internals, including a forged steel crankshaft, forged connecting rods, and forged aluminum pistons, are designed to handle significantly more power. With the right combination of forced induction upgrades and supporting modifications, the Hellcat can reliably exceed 750 horsepower at the wheels — translating to over 850 at the crank. This build guide outlines the essential upgrades you need to hit that milestone while maintaining streetability and reliability.

Forced Induction Upgrades: Pushing Past the Stock Blower

The factory IHI supercharger is efficient for stock levels, but it becomes a bottleneck above 700 wheel horsepower. To consistently achieve 750+ hp, you have two primary routes: upgrade the supercharger or add a secondary forced induction system. Below are the most proven options.

Supercharger Upgrades

Replacing the stock supercharger with a larger unit is the most common path. These systems bolt onto the Hellcat’s existing intake manifold provisions and provide instant power gains across the RPM range.

Whipple 3.0L or 4.5L Supercharger – Whipple’s twin-screw design delivers massive volumetric efficiency. The 3.0L is ideal for 750-850 hp on pump gas, while the 4.5L can support 1,000+ hp with race fuel or E85. Expect gains of 150-200 hp over stock with a proper tune.
Magnuson Heartbeat 2650 – This Roots-style supercharger offers excellent low-end torque and consistent power delivery. It’s a popular choice for daily-driven Hellcats because it retains factory drivability while adding 100-150 hp.
Ken Bell 3.8L Twin-Screw – Ken Bell’s unique billet rotor pack design reduces heat soak and improves efficiency. It pairs well with high-flow intercoolers and can push 800+ hp with supporting mods.

External resource: For detailed dyno comparisons, check out Hot Rod’s supercharger shootout.

Turbocharging: An Alternative Route

While less common on Hellcats due to space constraints, a single or twin turbo setup can deliver 750+ hp with superior thermal efficiency. Kits from Hellion Power Systems or Boost District are available for the Challenger chassis. Turbocharging requires custom headers, intercooler piping, and a blow-off valve system. Expect higher peak power potential but more complex installation and tuning.

Intercooler System Improvements

No matter which forced induction upgrade you choose, heat management is critical. The stock intercooler bricks are undersized for sustained high boost. Upgrade to a dual-core brick intercooler or a front-mount intercooler (FMIC) conversion. Companies like Kooks and Zeus Diesel offer large FMIC kits that drop intake air temperatures by 40-60°F, stabilizing power on hot days or during repeated pulls.

Larger intercooler bricks – Drop-in replacements that increase core volume by 40% without major modifications.
Heat exchanger upgrade – A higher-flow coolant pump and a larger heat exchanger (such as the one from Mishimoto) improve the intercooler system’s capacity.
Meth/Water injection – For serious track use, a direct port methanol injection system can further cool intake air and suppress detonation.

Supporting Modifications: The Foundation for Reliability

Brute force without support leads to broken parts. Every 750+ hp Hellcat requires a thorough suite of supporting mods to survive the extra stress. Below are the essential categories.

Fuel System Upgrades

Stock fuel injectors and pump can handle around 750-800 crank horsepower, but beyond that they run out of capacity. For 750+ wheel horsepower, you need:

High-flow fuel injectors – Upgrade to 1,000 cc/min or larger. Injector Dynamics (ID1050x) and FIC (Fuel Injector Clinic) make direct-fit units.
Dual upgraded fuel pumps – The stock in-tank pump can be supplemented with a secondary pump or replaced with a Fore Innovations twin-pump system that supports up to 1,000 whp.
Larger fuel lines – Increase from -6AN to -8AN or -10AN lines to reduce pressure drop. A fuel pressure regulator capable of handling higher flow is also recommended.
E85 conversion – If you want to run ethanol, you’ll need stainless steel lines, E85-compatible injectors, and a sensor for the ECU (Flex Fuel capability is factory on some later models, but tuning is still required).

External resource: A comprehensive fuel system guide is available at Fore Innovations’ website.

Exhaust System – Let It Breathe

Restrictive exhaust robs horsepower. To support 750+, you need to minimize back pressure before and after the supercharger.

Long-tube headers – American Racing Headers (ARH) or Kooks 1-7/8″ to 2-1/4″ primary tubes shed 20-30 lbs of weight and gain 30-50 hp over stock manifolds.
High-flow catalytic converters – If you must retain cats for emissions, use 200-cell metallic cats. Better yet, go with catless downpipes for a track-only build.
Cat-back exhaust – A 3-inch system from Borla or Corsa improves flow while tuning the sound. Avoid restrictive mufflers; a straight-through design yields best results.
X-pipe or H-pipe – Adding an X-pipe before the mufflers equalizes exhaust pulses and adds peak torque.

Cooling System Enhancements

Higher horsepower generates more heat. The Hellcat’s cooling system needs attention to prevent thermal runaway during spirited driving.

High-capacity radiator – Mishimoto or CSF all-aluminum radiators cool better than the stock plastic-tank unit. Look for a 2-row or 3-row core.
Oil cooler upgrade – The factory oil cooler is marginal for sustained track use. A Setrab or Mocal 34-row cooler with -10AN lines can keep oil temperatures below 250°F.
Lower thermostat – A 160°F or 170°F thermostat allows coolant to circulate earlier, keeping peak temps lower during heavy loads.
Electric fan upgrade – If the factory fan struggles, consider a Spal PWM fan kit that moves more air at idle and low speeds.

Drivetrain & Transmission Support

The stock 8HP70 eight-speed automatic (or the manual option with its own limitations) can handle 750 hp with careful driving, but reliability mods are wise.

Torque converter – A billet converter with a higher stall speed (3,000-3,200 rpm) helps spool the blower harder and reduces heat in the transmission.
Transmission cooler – A Derale plate-style cooler with a thermostat bypass keeps the ZF eight-speed cool during passes.
Driveshaft – The stock carbon fiber driveshaft is actually decent, but if you upgrade to a one-piece aluminum shaft, you’ll reduce rotating mass and handle more torque.
Rear differential – Swap the factory open diff for a Wavetrac or Eaton TrueTrac limited-slip unit, and upgrade axles to DSS (Drive Shaft Shop) half-shafts if you’re launching hard or running sticky tires.

Suspension and Tires – Getting the Power to the Ground

750+ hp is useless if the car can’t hook. Challenge the chassis dynamics with these upgrades:

Adjustable coilovers – KW or BC Racing coilovers with stiff spring rates (500-700 lb/in front, 700-900 rear) reduce squat and body roll.
Drag pack wheels and tires – For the drag strip, run 17″ or 15″ front runners and 18″ rear wheels with Mickey Thompson ET Street R (325/45R18) or Hoosier DR2 slicks.
Upper and lower control arms – BMR or UMI adjustable rear arms let you dial in pinion angle and eliminate wheel hop.
Sway bars – A larger rear sway bar (like the 32mm one from H&R) flattens cornering and reduces understeer.

Custom Tuning: The Glue That Holds It Together

All the hardware in the world means nothing without proper calibration. The Hellcat’s ECU is locked by security measures, so you’ll need a reputable tuner who can unlock and reprogram it. Options include:

HP Tuners – The most common software; many shops (like Tuning by Barth) offer remote tuning with emailed files.
DiabloSport Trinity 2 – A handheld unit with canned tunes, but custom dyno tuning yields better results.
ProCharger or Whipple-specific calibrations – Some supercharger kits include base tunes, but always have a professional refine them.

A proper tune addresses fuel trims, spark timing, boost control (if using electronic boost controller), transmission shift points, and knock detection. For 750+ hp on pump gas, expect around 15-17 psi of boost; on race gas or E85, you can push 20+ psi with additional timing.

External resource: Learn more about Hellcat tuning strategies at HemiTuner’s guide.

Budget and Build Timeline Expectations

Building a 750+ hp Hellcat isn’t cheap. Here’s a rough breakdown of parts and labor:

Estimated Costs for a 750+ HP Hellcat Build
Component	Cost (Parts & Labor)
Supercharger upgrade (Whipple 3.0L kit)	$6,500 – $8,000
Intercooler/front-mount kit	$1,500 – $3,000
Fuel system (injectors, pumps, lines)	$2,500 – $4,000
Exhaust (headers, cat-back, cats)	$2,000 – $3,500
Cooling (radiator, oil cooler)	$800 – $1,500
Drivetrain (torque converter, diff, axles)	$3,000 – $5,000
Suspension & tires	$2,000 – $4,000
Tuning (custom dyno + remote support)	$800 – $1,200
Total estimate	$19,100 – $30,200

Labor charges vary; expect 30-60 hours of shop time for a full build. Budget an additional $3,000-$6,000 for a professional installation if you’re not DIY-equipped.

Maintenance and Long-Term Reliability

Once you hit the 750+ hp mark, the Hellcat becomes a more demanding machine. Plan for:

Frequent oil changes – Use a high-zinc 5W-50 synthetic (like Royal Purple) every 3,000-5,000 miles.
Spark plug changes – Replace with colder NGK plugs (gap to 0.028″) every 15,000 miles.
Intercooler fluid flush – Use distilled water + Water Wetter or a dedicated high-conductivity coolant annually.
Belt inspection – The supercharger belt gets heavy stress; replace it every two years or if you see glazing.
Dyno verification – Have the car re-tuned if you change elevation, fuel type, or add new parts.

Conclusion

Building a 750+ horsepower Dodge Challenger 6.2 Hellcat is a rewarding project that transforms a factory monster into a true street-and-strip weapon. By upgrading the supercharger (or adding a turbo), fortifying the fuel system, improving airflow, and reinforcing the drivetrain, you can achieve reliable power well beyond the stock numbers. Never skip the supporting mods — they are the difference between a weekend warrior and a grenade waiting to happen. Invest in professional tuning, use quality components, and enjoy the surge of power that only a properly built Hellcat can deliver.