Complete Hellcat Engine Swap Parts Checklist

A Hellcat engine swap is not a project you figure out as you go. Every supporting system needs to be planned, sourced, and confirmed before the engine arrives. Missing one component on installation day means delays, additional shipping costs, and in some cases a partially assembled vehicle sitting idle while you wait for a part.

This checklist covers every component category involved in a Hellcat swap. Work through it before you order the engine. Use it again when the engine arrives to confirm everything is on hand before the install begins.

How to Use This Checklist

This list is organized by system. Each section covers what you need, why you need it, and what to confirm before purchasing. Not every item applies to every build. Some categories such as the transmission section depend entirely on your specific application. Read each section, mark what applies to your build, and confirm sourcing before moving forward.

Some items are universal across all Hellcat swaps. Others depend on your target chassis, your transmission choice, and your intended use. Those variables are noted where relevant.

Section 1: The Engine Package

Before anything else, confirm exactly what comes with the engine you are buying. The engine package determines what you still need to source separately.

Confirm With Your Seller Before Purchasing

Complete donor vehicle VIN provided
Mileage verified from donor vehicle records
Compression test performed and actual cylinder readings available
Oil condition assessed and documented
Supercharger shaft play checked and result documented
Warranty terms confirmed in writing

Confirm What Is Included With the Engine

Long block assembly: block, heads, valvetrain, timing components
Supercharger assembly included or sourced separately
Intake manifold included or sourced separately
Fuel rails and injectors included or sourced separately
Throttle body included or sourced separately
Engine sensors: which ones are attached and which are missing
Valve covers included
Oil pan: confirm whether factory pan is included and whether it suits your chassis
Accessory drive components: alternator, A/C compressor, power steering pump if applicable
Engine wiring harness included or sourced separately
ECU and PCM included or sourced separately

Note: A long block without the supercharger is a fundamentally different purchase from a complete engine. Confirm component inventory in writing before the engine ships.

Section 2: Engine Management and Electronics

The factory Hellcat PCM is VIN-locked to the original donor vehicle. This is one of the most critical planning decisions in any Hellcat swap.

For Direct Replacement in the Original Vehicle

Factory PCM retained from original vehicle
PCM reflash to recognize replacement engine confirmed with dealer or tuner
Engine wiring harness from original vehicle confirmed functional

For Swap Into a Different Chassis

Choose one ECU solution and plan the wiring around it before ordering the engine.

Option A: Standalone Engine Management System

Standalone ECU selected and ordered (Holley HP EFI, Holley Dominator, AEM Infinity, or equivalent)
Swap-specific wiring harness for Hellcat application ordered
Base calibration file sourced or tuner confirmed for startup tune
Wideband oxygen sensor kit sourced if not included with ECU

Option B: Factory PCM with Anti-Theft Bypass

Factory PCM sourced from same donor vehicle as engine
Anti-theft bypass solution identified and sourced
PCM programming confirmed with a shop experienced in Hellcat PCM work

Option C: Aftermarket PCM Reflash Solution

Aftermarket reflash solution identified and confirmed compatible with your engine variant
Shop experienced in this solution confirmed and scheduled

All Swap Applications

Crankshaft position sensor present on engine or sourced
Camshaft position sensors present or sourced
Coolant temperature sensor present or sourced
Oil pressure sensor present or sourced
Knock sensors present or sourced
Mass airflow sensor sourced and compatible with ECU solution
Throttle position sensor present or sourced
Manifold absolute pressure sensor present or sourced if applicable
Oxygen sensors sourced and compatible with ECU solution
Engine ground straps planned and sourced

Section 3: Motor Mounts

Motor mount selection must be confirmed before finalizing engine position. Engine position affects every other component in the swap including oil pan clearance, exhaust routing, and accessory drive layout.

Classic Mopar Platforms (A-body, B-body, E-body)

Aftermarket Gen III HEMI motor mount kit identified for specific chassis
Frame bracket bolt pattern confirmed for your specific chassis year
Engine bracket bolt pattern confirmed for Gen III HEMI block
Engine position confirmed for steering shaft clearance
Engine position confirmed for firewall clearance
Engine position confirmed for hood clearance with supercharger height

Non-Mopar Platforms

Custom motor mount fabrication planned or fabricator confirmed
Engine position established before fabrication begins
Steering shaft clearance confirmed at planned engine position
Firewall clearance confirmed at planned engine position
All clearances re-confirmed with engine physically in the bay before welding mounts

All Platforms

Motor mount hardware sourced (grade 8 bolts, washers, lock washers, nuts)
Engine leveler or engine hoist confirmed available for installation

Section 4: Oil Pan and Oiling System

The factory Hellcat oil pan fits the factory Challenger and Charger chassis. In most swap applications it does not clear the target chassis frame rails, crossmember, or steering components.

Oil pan clearance checked with factory pan before ordering a swap pan
Swap-specific oil pan identified for your chassis and motor mount position
Oil pan sump location confirmed to clear frame rails and crossmember
Oil pan depth confirmed for ground clearance in your application
Oil pan gasket sourced
Oil pan drain plug and washer sourced
Oil pickup tube confirmed compatible with swap pan
Oil pickup tube O-ring or gasket sourced
Correct engine oil volume for swap pan confirmed (may differ from factory spec)
High-quality full synthetic oil sourced: 5W-20 factory spec or 5W-30 or 0W-40 for performance use
Oil filter sourced

Section 5: Transmission and Bellhousing

The Hellcat uses a Gen III HEMI-specific bellhousing bolt pattern. Confirm transmission compatibility before ordering either the engine or the transmission.

Identify Your Transmission

Transmission identified and confirmed for your application
Transmission torque capacity confirmed adequate for Hellcat output (650 lb-ft minimum rating recommended)

Common Transmission Options

Transmission	Notes
TorqueFlite 8HP90	Factory Hellcat automatic, strongest direct option
Tremec TR-6060	Factory Hellcat 6-speed manual
Tremec T56	Common swap manual, requires bellhousing adapter
Tremec TKX	Compact 5-speed manual, requires bellhousing adapter
GM TH400	Non-Mopar builds, requires bellhousing adapter
TorqueFlite 727 or 904	Classic Mopar builds, requires bellhousing adapter

Bellhousing and Adapter

Bellhousing adapter identified if using a non-factory transmission
Adapter confirmed compatible with your specific engine variant and transmission model
Input shaft length confirmed compatible with adapter and transmission combination
Adapter hardware sourced

Clutch and Flywheel (Manual Transmissions)

Flywheel sourced and confirmed for Hellcat crankshaft flange and manual transmission
Clutch disc spline count confirmed compatible with transmission input shaft
Clutch pressure plate and disc rated for Hellcat torque output
Throwout bearing sourced
Clutch fork sourced if applicable
Pilot bushing or bearing sourced
Hydraulic clutch master cylinder and slave cylinder sourced if not carried over from original vehicle

Flexplate (Automatic Transmissions)

Flexplate sourced and confirmed for Hellcat crankshaft flange and automatic transmission
Flexplate bolt pattern confirmed for torque converter
Torque converter sourced and rated for Hellcat output

Driveshaft

Driveshaft length measured with engine and transmission in final position
Driveshaft ordered to correct length, diameter, and end yoke specifications
U-joints sourced if rebuilding existing driveshaft
Driveshaft loop or safety loop sourced if required for your application

Section 6: Fuel System

The Hellcat runs a high-pressure returnless direct injection fuel system. This is one of the most commonly underestimated planning requirements in a Hellcat swap.

High-Pressure Side

Cam-driven high-pressure fuel pump confirmed present on engine assembly
High-pressure fuel rails and injectors confirmed present or sourced
High-pressure fuel line from tank to engine sourced and rated for DI operating pressures
High-pressure fuel line fittings confirmed compatible

Low-Pressure Supply Side

In-tank fuel pump module confirmed compatible with DI system inlet requirements
Fuel pump flow rate confirmed adequate for Hellcat fuel demand at full output
Fuel tank confirmed compatible with pump module and fuel line routing
Fuel filter sourced if applicable to your system configuration
Fuel pressure regulator sourced if required for your configuration

Fuel Lines and Fittings

Fuel supply line routed and confirmed clear of heat sources and moving components
Fuel return line routed if applicable
All fuel line fittings confirmed compatible and rated for operating pressures
Fire-safe fuel line material confirmed for runs near exhaust components

Fuel Type

Premium fuel supply planned: minimum 91 octane, 93 octane preferred
Fuel system components confirmed compatible with ethanol content in your local fuel supply if applicable

Section 7: Main Engine Cooling System

The Hellcat requires a main cooling circuit capable of handling the thermal output of a supercharged 700-plus horsepower V8.

Aluminum radiator sourced and confirmed adequate capacity for Hellcat heat rejection
Radiator confirmed to fit your chassis with appropriate mounting provisions
Upper and lower radiator hoses sourced and routed without sharp bends or contact with hot components
Coolant overflow or degas tank sourced and mounted
Electric cooling fan or mechanical fan solution confirmed and sourced
Fan controller sourced if using electric fans
Fan shroud sourced or fabricated to direct airflow through radiator core
Thermostat sourced at correct temperature rating for Hellcat application
Thermostat housing sourced or confirmed present on engine
Water pump confirmed present on engine or sourced
Coolant sourced: OAT or HOAT per factory specification for your model year
Coolant bleed procedure identified before filling system

Section 8: Supercharger Intercooler Cooling Circuit

This is the cooling system component most often overlooked in Hellcat swap planning. The intercooler circuit is entirely separate from the main engine cooling circuit and requires its own components.

Intercooler heat exchanger sourced and mounting location identified at front of vehicle
Heat exchanger mounting position confirmed to receive adequate airflow
Heat exchanger confirmed to fit in available front-end space alongside main radiator
Intercooler coolant pump sourced and rated for Hellcat application
Intercooler coolant reservoir sourced and mounting location identified
Intercooler supply and return hoses routed and sourced
Intercooler hose fittings confirmed compatible
Intercooler circuit coolant sourced
Intercooler circuit bleed procedure identified before running engine under load
Intercooler pump power supply wired to engine run circuit so pump operates whenever engine runs

Critical note: The intercooler circuit must be fully functional and fully bled before the engine runs under boost. Without intercooler coolant circulation, intake air temperatures climb rapidly under boost and detonation risk increases significantly.

Section 9: Exhaust System

The factory Hellcat exhaust manifolds fit the factory Challenger and Charger chassis. Most swap applications require different exhaust manifolds or headers.

Exhaust manifold or header option identified for your chassis and motor mount position
Header tube routing confirmed clear of steering components, frame rails, and floor
Header flange pattern confirmed for Gen III HEMI cylinder head bolt pattern
Collector size and location confirmed for your downstream exhaust routing
Downpipes or mid-pipes sourced
Catalytic converters sourced if required for your application
Mufflers sourced
Exhaust hangers and isolators sourced
Oxygen sensor bungs confirmed in correct locations for your ECU solution
Exhaust system thermal clearance confirmed from floor, fuel lines, and brake lines

Section 10: Accessory Drive

The factory Hellcat accessory drive suits the factory Challenger and Charger engine bay. Swap applications typically require a modified or custom accessory drive layout.

Alternator confirmed present or sourced, confirmed compatible with your charging system requirements
Alternator output confirmed adequate for your electrical loads including intercooler pump
Power steering solution identified: factory hydraulic pump, electric power steering conversion, or fixed ratio
Air conditioning: confirm whether you are retaining A/C and source compatible compressor and bracket if so
Accessory drive belt routing confirmed with all pulleys in final position
Belt tensioner confirmed functional or sourced
Idler pulleys confirmed functional or sourced
Accessory drive belt sourced to correct length for your configuration
Supercharger drive belt sourced
Supercharger belt tensioner confirmed functional

Section 11: Intake and Air Induction

Air intake system sourced and routed from filter to supercharger inlet
Cold air intake or air box sourced and positioned away from heat sources
Air filter sourced and confirmed correct for intake system
Intake tube confirmed sealed with no air leaks between filter and supercharger inlet
Mass airflow sensor mounting location confirmed and compatible with ECU solution
Intake tube routing confirmed clear of moving components and heat sources
Supercharger inlet confirmed free of debris before first startup

Section 12: Ignition System

Coil-on-plug ignition coils confirmed present on engine or sourced
Spark plugs sourced at correct heat range for your application
Spark plug gap confirmed to factory specification before installation
Coil wiring confirmed connected and routed away from heat and moving components
Ignition timing base setting identified for your specific build combination before first startup

Section 13: Engine Bay Preparation

Before the engine goes in, the engine bay needs to be ready.

Engine bay cleaned and inspected for rust, damage, or components needing repair
Firewall grommets identified for all new wiring and line pass-throughs
Existing wiring that will not be used removed or secured away from heat and moving components
Engine bay ground points identified and prepared
Battery and battery cables confirmed adequate for Hellcat starter current demands
Battery location confirmed and cable routing planned
Fuse and relay panel location identified for engine management system

Section 14: Chassis and Drivetrain Supporting Components

Rear differential confirmed adequate for Hellcat torque output
Rear axle shafts confirmed adequate for your power level if applicable
Rear suspension confirmed adequate for increased torque and weight
Brake system confirmed adequate for the vehicle’s increased performance capability
Brake booster vacuum source identified if your application uses vacuum-assisted brakes (Hellcat does not produce significant vacuum, so an electric vacuum pump or hydroboost system may be required)
Engine and transmission crossmember or mount confirmed for new drivetrain combination

Section 15: Fluids and Consumables

Fluids are the most commonly forgotten category until installation day.

Engine oil: full synthetic, correct viscosity, adequate quantity for your oil pan volume
Oil filter
Coolant: correct specification and adequate quantity for main circuit
Intercooler coolant: correct specification and adequate quantity for intercooler circuit
Transmission fluid: correct specification for your transmission
Differential fluid if applicable
Power steering fluid if retaining hydraulic steering
Brake fluid if brake system was opened during installation
Threadlocker for critical fasteners
RTV sealant if applicable to your gasket configuration
Anti-seize for spark plugs
Assembly lube for bearing surfaces during installation

Section 16: Tools and Equipment for Installation Day

Engine hoist with adequate capacity for Hellcat engine weight (approximately 550 to 580 lbs with supercharger)
Engine leveler for precise angle control during installation
Transmission jack
Torque wrench set covering required torque ranges
Socket set including specialty sizes for Hellcat fasteners
Breaker bar
Compression tester if performing pre-installation compression check
Scan tool capable of communicating with your ECU solution
Multimeter for wiring verification
Timing light if using a distributor-based ignition solution
Fuel pressure gauge for verifying fuel system pressure at startup
Coolant pressure tester for leak checking before first startup
Fire extinguisher accessible during first startup

Section 17: First Startup Checklist

Before the first startup, confirm each of the following.

All coolant lines connected and clamped
Main cooling system filled and bled
Intercooler circuit filled and bled
All fuel connections made and pressure tested before cranking
All electrical connections confirmed and secured
No tools or loose components remaining in engine bay
Supercharger inlet clear of all debris and securely connected
Oil filled to correct level
Oil pressure confirmed by cranking engine with ignition disabled until oil pressure registers before first fire
Ignition timing base set per specification for your build
Fuel pressure confirmed at specification with key on engine off
Fire extinguisher accessible
First startup performed with someone watching for leaks while another person monitors gauges

Section 18: Post-Startup and Break-In

Check all fluid levels immediately after first startup
Check for coolant, oil, and fuel leaks at operating temperature
Confirm intercooler pump is operating at operating temperature
Monitor coolant temperature for correct warm-up rate and stable operating temperature
Monitor oil pressure at idle and at operating RPM
Allow break-in period before sustained hard use: 500 miles minimum of varied RPM driving without extended full-throttle runs
First oil change at 500 miles to remove initial wear debris
Professional tune scheduled before sustained hard use

Where to Source a Verified Hellcat Engine

A complete checklist is only as useful as the engine it is built around. At McClain Auto Part, we carry verified low-mileage 6.2L Hellcat engines with compression testing performed on all eight cylinders, oil condition assessed, supercharger shaft play checked, and mileage verified from donor vehicle records before the engine ships. Every unit comes with a 6-month warranty against internal mechanical defects and ships on a secured freight pallet from our Cleveland, Ohio warehouse.

Call us at +1(216) 230-5433 or email sales@mcclainautopart.com with your application details and we confirm the engine variant, included components, compatibility, and current availability before you commit to anything.