Engine Specifications

This engine is a great performance upgrade for those looking to get a little more power from their vehicle or can be used to retrofit into a muscle car application. By teaming up with Comp Cams, ATK takes a remanufactured 5.7L Hemi and upgrades the camshaft, springs, and pushrods to make a reliable 400+ horse power. This engine is used in 2003-2008 Chargers, Magnums, Chrysler 300's, Ram Trucks, Commanders, and Grand Cherokees.

• Horsepower: 400 hp
• Torque: 400 lb/ft

Block Information:

• Seasoned OE Gen III HEMI 2003-2008
• Bore/Stroke: 3.920" x 3.580"
• Displacement: 345ci / 5.7L

Rotating Assembly:

• Crankshaft: OE Cast
• Rods: OE
• Compression Ratio: 9.6:1
• Pistons: Hypereutectic
• Rings: Moly

Camshaft Specs:

• Camshaft: Hydraulic roller
• Cam Duration @ .050": Intake 216 / Exhaust 220
• Cam Lift: Intake .528" / Exhaust .531"
• Lobe Separation Angle: 113lsa
• Timing Chain: OE

Cylinder Head Information:

• Cylinder Heads: OE 
• Combustion Chamber: 85cc
• Intake Runner: 161cc
• Valve Size: 2.00" Intake / 1.50" Exhaust
• Rocker Arms: OE Shaft mount

• Timing: Computer ECM Tuning REQUIRED

Notes: 

• Car and truck applications with MDS and has power steering holes in front of heads.
• An ECM tune is required. A complete check of the fuel system is highly recommended to avoid fueling issues that can lead to fuel wash and other catastrophic failures that are not covered under warranty (injectors, pump, filters, etc). With this camshaft Comp Cams made 47hp+ over the factory ratings and had strong mid-range gains.

 Disclaimer: The parts listed are ATK's recommendations of parts to be used to obtain the power figures listed. Power figures can vary based on parts used by the end user. Some modifications to the vehicle may be required using these and or other aftermarket parts.

Engine Break-In Procedure

Use or break-in oil or conventional (non-synthetic) 10w30 oil with zinc additive for the first 500 miles of operation.  Do not drive for long periods at any single speed, always vary your speed. Do not tow a trailer or put other heavy loads on the vehicle. It is best to avoid long periods of idling during this period. Check the engine oil and coolant levels daily. 

Engines with flat tappet hydraulic cams only - Run the engine between 2,000 and 2,500 RPM's, with no-load on the engine for the first 30 minutes. Let the engine cool down completely and repeat process 2-3 more times. Do not idle the engine for any extended period at this time, this is critical to break in the camshaft.

At 500 Miles change the engine oil and filter using conventional (non-synthetic) oil with a zinc additive. Check fuel and ignition settings, adjust valves (where applicable).  Drive the next 500 miles normally, without high RPM's (below 5000 RPM), hard use, or extended periods of high loading or long periods of idling.

Change the oil and oil filter again at 1,000 miles. Continue using conventional (non-synthetic) oils and zinc additive, until about 4,000 miles. At that point, you may run a quality 10w30 synthetic oil if you choose. Use of oil with zinc or a zinc additive for the life of your engine is recommended. 

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

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