ATK HP97 Chevy LM7 5.3L 99-07 Truck Base Engine 385HP

Item #31974 Brand:ATK Engines

Made in the USA
ATK HP97 Chevy LM7 5.3L 99-07 Truck Base Engine 385HP
HP97 ATK Chevrolet 5.3 H.P. 385HP Engine Long Block
* ** THIS ITEM IS TEMPORARILY OUT OF STOCK *** FREE SHIPPING on ATK Engines. This item ships directly from the manufacturer and is not available for store pickup. Some engines are made-to-order or can be backordered. Delivery can be delayed up to 5 to 6 weeks but typically ship within 2 weeks.

*Truck Freight Delivery Notice - Driver will only deliver this item to your curb. It is your responsibility to transport the item from curb to your garage.

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ATK HP97 Chevy LM7 5.3L Base Engine, or Stage 1 Engine, is designed for those that may have their own component parts already and who also are interested in completing out the build themselves. A GM base engine typically consists of the following: Short Block, Camshaft, Timing set, Cylinder heads, Valve covers, Timing cover, oil pan, oil pump & pick up tube.

Engine Specifications:

  • HP: 385
  • TQ: 390
  • Block: Seasoned OE LM7/5.3L iron
  • Bore/Stroke: Up to 3.809 x 3.622
  • Displacement ( 323
  • Crankshaft: OEM GM 24 tooth reluctor wheel
  • Rods: Stock GM
  • Pistons: Hypereutectic 9.5:1 compression
  • Rings: Moly
  • Camshaft: Hyd. roller
  • Cam Specs: Custom performance grind
  • Cylinder Heads: OE aluminum 61.15cc 1.89/1.55
  • Rocker Arms: OE powdered metal 1.7 ratio
  • This engine was designed to be a performance upgrade for a 1999-2007 Chevy Truck LM7 or LS swap in a hot rod. Expect big mid to upper end power, will have a noticeable idle. For optimal Performance you will need headers, chassis dyno tune and upgraded injectors. Cam Specs will come with the engine.

    ATK specializes in muscle. With the highest quality internal parts and Dyno Proven combinations of every engine built, ATK is able to add the most bang for your buck and back it up with an industry leading warranty.

    Don't forget the engine paint!
    Engine Paint


    ATK HP97 Chevy LM7 5.3L 99-07 Truck Base Engine 385HP


    • Horsepower: 385+
    • Torque: 390+
    • Block: GM 5.3L Iron LM7
    • Bore/Stroke: Up to 3.809 x 3.622
    • Year Range: 1999-2007
    • Displacement: 323 C.I.D.
    • Crankshaft: OEM GM 3.622" Stroke Internally Balanced 24 tooth Reluctor wheel .857" Flange
    • Connecting Rods: OE GM Forged Powder Metal 6.093" Stock Bolts
    • Pistons: Hypereutectic Dish
    • Piston Rings: Moly Rings
    • Compression Ratio: 9.5:1 Compression
    • Camshaft: Hydraulic Roller
    • Camshaft Specifications: Custom Grind
    • Camshaft Bearings: Installed & Clocked to OEM Position
    • Cylinder Heads: OE Aluminum 61.15cc 1.89/1.55
    • Freeze Plugs: Brass Installed & Sealed
    • Rocker Arms: OE Powdered Metal 1.7 Ratio
    • Oil Galley Plugs: Installed & Sealed
    • Weight: 385


    Recommended Components:

    • Oil- 5W30
    • Fuel System – OE EFI System
    • Intake – Stock Fuel Injected
    • Balancer- Stock Internally Balanced
    • Flex plate/Flywheel- Stock Internally Balanced
    • Spark Plug- Stock
    • Spark Plug Gap- .035”
    • Timing- Set To Factory Specifications Via PCM Module (Tune Required)
    • Firing Order- Stock
    • Fuel - 91 Octane
    • Recommended Stall Converter- stock or 1800
    • Exhaust- 1 5/8 or 1 3/4 Headers

    Shipping Instructions and Core Information

    Shipping is free and lift gate will be provided.

    There is no core charge for this engine. You will not be required to send a core back to the manufacturer.

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