A Hellcat Demon 170 engine in a Chrysler 300 is a rare, high-performance modification that combines a modern supercharged V8 with a full-size luxury sedan

The Chrysler 300 SRT Demon 170 swap takes the 6.2-liter supercharged V8 from the 2023 Dodge Charger SRT Hellcat Redeye Demon 170 and installs it into a Chrysler 300 body. The Demon 170 engine produces 1,025 horsepower on 170-octane racing fuel (or 950 horsepower on standard 93-octane pump gas). This is not a factory option — it is a custom build performed by independent shops, and the result is a sedan that weighs around 4,500 pounds but generates power typically found in purpose-built drag cars.

The swap requires significant structural and electrical work. The engine bay must be modified to fit the supercharger and intake manifold. The transmission, cooling system, fuel system, and engine computer all need to be compatible with the 300's frame and wiring. Shops that perform this work typically charge between $15,000 and $30,000 in labor alone, on top of the cost of the donor engine and transmission.

Key Takeaways

  • The Demon 170 engine produces 1,025 horsepower on racing fuel and requires extensive modification to fit inside a Chrysler 300 frame.
  • A completed swap typically costs $50,000 to $80,000 total when you include the donor engine, transmission, labor, and supporting modifications.
  • The resulting vehicle will not pass standard emissions testing in most states because the engine computer and exhaust system are not certified for that body style.
  • Insurance companies often refuse to cover swapped vehicles or charge premiums that exceed the cost of the car itself.
  • Resale value is unpredictable because the vehicle is not a factory model and has no manufacturer warranty or service history for the powertrain.

Engine specifications and what the numbers mean

The Demon 170 is a 6.2-liter supercharged V8 with an 8.0:1 compression ratio. On 170-octane racing fuel (a blend sold at select tracks and fuel suppliers), it makes 1,025 horsepower and 945 pound-feet of torque. On 93-octane pump gas, the engine computer reduces boost pressure and the output drops to 950 horsepower and 850 pound-feet of torque. The engine is paired with an 8-speed automatic transmission rated for that power level.

For comparison, a stock 2023 Charger SRT Hellcat Redeye makes 807 horsepower on pump gas. The Demon 170 adds a larger supercharger, higher boost pressure, and a different fuel map. In a Charger, the Demon 170 can accelerate from 0 to 60 mph in approximately 2.9 seconds and run a quarter-mile in the low 10-second range. In a heavier 300, acceleration will be slightly slower, but still well into supercar territory.

Why emissions and registration become problems

A Chrysler 300 with a Demon 170 engine will not pass emissions testing in states that require it. The engine computer and exhaust system are calibrated for a Charger, not a 300. The vehicle identification number (VIN) still shows a 300, but the powertrain is not certified for that model. Most state DMVs will not issue a title or registration for a vehicle with a mismatched engine and body unless the owner can provide factory documentation — which does not exist for a custom swap.

Some states allow registration under a "custom vehicle" or "kit car" classification, but this typically requires a safety inspection, proof of the donor engine's origin, and documentation of all modifications. Even then, the vehicle may be restricted from public roads or limited to show-and-display use only. A few states have no emissions requirement and will register almost anything, but moving a swapped vehicle across state lines can trigger registration and title issues in the destination state.

Insurance and liability coverage

Most major insurance companies will not insure a vehicle with an engine swap, or they will require the owner to disclose the modification and accept a much higher premium. Some insurers treat swapped vehicles as total losses waiting to happen and straightforward decline coverage. Others will insure the car but exclude the engine and transmission from coverage, meaning if the supercharger fails or the engine seizes, the owner pays for repairs out of pocket.

The liability risk is real from an insurer's perspective. A 1,000-horsepower sedan is not a vehicle the original manufacturer tested or designed for. Crash test data does not explore. Structural integrity under extreme acceleration is unknown. If the vehicle is involved in an accident, the insurer may argue that the modification contributed to the loss, and coverage disputes can drag on for months.

Cost breakdown for a complete swap

A Demon 170 engine and transmission from a donor Charger typically cost $8,000 to $15,000 if purchased used from a salvage yard or private seller. A new crate engine from Chrysler or an authorized dealer costs significantly more. Labor to remove the original 300 engine, modify the bay, install the new engine, and integrate all systems ranges from $15,000 to $30,000 depending on the shop's experience and the condition of the 300 being modified.

Supporting modifications add to the total. The cooling system must be upgraded to handle the heat from the supercharger. The fuel system may need a larger pump and injectors. The suspension and brakes should be upgraded to handle the power and weight transfer. Exhaust work, engine tuning, and dyno testing can add another $5,000 to $10,000. A realistic total for a professional, drivable swap is $50,000 to $80,000, not including the cost of the 300 itself.

Resale value and long-term ownership

A Chrysler 300 with a Demon 170 swap has almost no resale market. The vehicle is not a factory model, so it does not have the brand recognition or collector value of a rare production car. It is too expensive and too specialized to appeal to used car buyers looking for a practical sedan. The next owner would inherit all the registration, insurance, and emissions problems, plus the risk that the engine or transmission fails outside of warranty.

Some buyers in states with no emissions testing or registration restrictions might pay $40,000 to $60,000 for a well-built swap, but that assumes the work was done by a reputable shop and documented thoroughly. Most swapped vehicles sell for a loss or sit unsold. If the owner ever needs to sell quickly — due to job loss, relocation, or financial hardship — the vehicle may be difficult to move at any price.

Why someone builds one anyway

Owners who pursue a Demon 170 swap are typically enthusiasts who want a unique, high-performance vehicle and have the budget to absorb the costs and risks. The appeal is the combination of a full-size luxury sedan with supercar-level power. A 300 is comfortable, seats five, and has a trunk. With a Demon 170 engine, it becomes a sleeper — a car that looks ordinary but performs extraordinarily. For someone who values the driving experience over resale value or practicality, the swap makes sense.

The build is also a technical challenge. Shops that specialize in engine swaps treat each project as a puzzle: how to fit the engine, route the cooling lines, integrate the computer, and make everything work together. The satisfaction of a completed swap — and the attention it draws at car shows or on the street — appeals to builders and owners who see the vehicle as a personal project rather than an investment.

Frequently Asked Questions

Will a Demon 170 swap make my 300 faster than a stock Charger Demon 170?

No. The Charger Demon 170 is lighter and has a factory-optimized chassis, suspension, and transmission tuning. A 300 with the same engine will be slightly slower due to the extra weight and the fact that the suspension and brakes were not designed for 1,000 horsepower. The 300 will still be extremely fast, but not faster than the factory car.

Can I register a swapped 300 if I live in a state with no emissions testing?

Possibly, but it depends on your state's rules for engine swaps and custom vehicles. Some states require proof that the engine came from a donor vehicle and documentation of all modifications. Others require a safety inspection. Contact your state DMV before starting the swap to understand what paperwork and inspections you will need.

What happens if the engine fails after the swap is done?

Repairs are your responsibility. The engine has no manufacturer warranty, and most independent shops will not warranty their labor beyond one year. If the supercharger fails or the engine develops internal problems, you will pay for parts and labor out of pocket. This is one reason many owners keep a large emergency fund set aside.

Can I drive a swapped 300 on public roads?

That depends on your state's registration and emissions laws. In states with strict emissions testing, you likely cannot register it for public road use. In states with no emissions requirement, you may be able to register it as a custom vehicle, but you should verify this with your DMV before building. Some states allow swapped vehicles only for show-and-display use.

How long does a Demon 170 swap typically take?

A professional shop usually needs four to eight weeks to complete a swap, depending on how much modification the 300 requires and whether any unexpected problems arise during the build. Custom fabrication, engine tuning, and testing can extend the timeline. Shops typically require a deposit upfront and payment in stages as the work progresses.