Menu

Shop

Garage

Cart

Account

Product Summary

Deluxe Crate Engine Crate Engine Type

    Comes as a Kit

    See more details

    Key Specs

    Crate Engine TypeDeluxe Crate Engine
    Engine Displacement323 cu. in.
    Horsepower475 horsepower
    Compression Ratio9.9:1
    Torque430 ft./lbs.
    See more specs

    Need To Know

    Truck Shipment

    Truck shipments must be pre-paid with a credit card, certified check or money order

    Quick and Easy Returns

    Return Policy

    Speedway Motors 91607096 Details

    Discover the ATK-tuned GM 5.3L LH6/LC9 engine, a limited-production (only 50 units) all-aluminum powerhouse designed for 2005-2009 GM trucks and SUVs. Enhanced with a performance camshaft package and built as a non-DOD/AFM engine, this 475 HP, 430 lb-ft torque beast features extra-thick cylinder sleeves for durability. Paired with the innovative Carbon LS1/LS2/LS6 pTR Intake Manifold, featuring modular velocity stacks (6.5–9” runners) and a carbon fiber plenum for reduced heat soak, this setup optimizes power across the RPM range. Complete the package with stylish two-piece valve covers, a CNC-machined aluminum timing cover, a 92mm billet throttle body, V-band cast iron exhaust manifolds, and a Silverline Series serpentine kit for a sleek, high-performance look. Perfect for LS swaps or upgrades, this engine delivers unmatched power and style. Dyno figures based on 750CFM carburetor, Vic Jr. intake, and 1-7/8” headers; EFI systems increase power output.

    Key Features:

    • High-Performance Engine: 475 HP, 430 lb-ft torque, non-DOD/AFM 5.3L aluminum block with performance cam (223/231 @50, .610/.617 lift, 112LSA).

    • Advanced Intake System: Carbon LS pTR manifold with modular velocity stacks, 10-11.4L plenum, and 105mm throttle body flange for superior airflow.

    • Premium Accessories: Two-piece valve covers hide LS coils, paired with a CNC-machined timing cover and Silverline Series serpentine kit for a standout look.

    • Durable Exhaust Solution: V-band cast iron exhaust manifolds ensure easy installation and improved exhaust flow for LS swaps.

    • Customizable Tuning: Optimize power with chassis dyno tune, upgraded injectors, and adjustable runner lengths for mid-range torque or high-RPM performance.

    Engine Specifications:

    • HP/TQ: 475 HP / 430 lb-ft

    • Block: New GM 5.3L Aluminum, 3.780” bore x 3.622” stroke, 323 cu.in

    • Camshaft: COMP Cams Hyd. roller (54-457-11)

    • Heads: OE 799/243 aluminum, 65cc, 2.000”/1.575” valves

    • Compression: 9.9:1 with hypereutectic flat-top pistons

    Recommended Components:

    • Fuel: 91 Octane, OE EFI or aftermarket intake

    • Oil: 5W30

    • Headers: 1-7/8” (application-dependent)

    • Stall Converter: 2200+ RPM

    • Timing: Factory specs via PCM tune

    Notes: Requires chassis dyno tune and AFM/DOD deactivation in ECM for swaps. Power varies with induction system. Includes valve and timing covers; no oil pan/pump.

    Disclaimer: Power figures depend on user-selected components. Verify component compatibility; vehicle modifications may be required. ATK reserves the right to substitute parts if needed.

    Specs

    • Horsepower: 475
    • Torque: 435 lb/ft
    • Block: GM 5.3L Aluminum LH6/LC9
    • Bore/Stroke: 3.780" x 3.622"
    • Year Range: 2005-2009
    • Displacement: 323CI
    • Crankshaft: OEM GM 3.622" Stroke Internally Balanced 24 tooth Reluctor wheel
    • Connecting Rods: OE GM
    • Pistons: Hypereutectic Flat Top
    • Piston Rings: Moly Rings
    • Compression Ratio: 9.9:1 Compression
    • Camshaft: Hydraulic Roller
    • Camshaft Specifications: 223/231 at .050 in .610/.617 lift with 112 LSA
    • Camshaft Bearings: Installed & Clocked to OEM Position
    • Cylinder Heads: OE 799/243 Aluminum 65cc 2.000" / 1.575" Valves
    • Freeze Plugs: Brass Installed & Sealed
    • Rocker Arms: OE Powdered Metal 1.7 Ratio
    • Oil Galley Plugs: Installed & Sealed
    • Weight: 412

    *Dyno figures are based on using a 750CFM carburetor and Vic Jr. intake manifold with 1 7/8 headers. With an EFI system this will pick up power.

    Warranty Information

    Click for details

    ATK warrants to the original purchaser that each engine sold by ATK shall be free of defects in materials and workmanship in the Continental 48 states. Subject to the following terms and Conditions:

    Award Winning Customer Support

    ATK is proud to have been named winner of the Frost & Sullivan North American Remanufactured Engines & Transmissions Aftermarket Customer Service Leadership of the Year Award. We are committed to making your purchase as easy and carefree as possible, and our on-hand service technicians are available to answer any technical questions.

    DEFINITIONS:

    Long Block: As used in this warranty refers to (basic block, cylinder head, valve train, internal components and sheet metal) as supplied by ATK, including those parts and accessories as supplied by ATK.

    Short Block: As used in this warranty refers to (basic block, crankshaft, connecting rods and pistons) as supplied by ATK, including those parts and accessories as supplied by ATK. Short Block’s carry a 90 day warranty from the date of sale with no provision for labor claims.

    Engines Built for Forced Induction/Racing Purposes/Elite Series: These engines will be noted as such. They will carry a limited warranty of 6 months against manufactures defects covering PARTS ONLY.

    TERMS:

    Stage I, II, and Stage III Warranty For Engines: These warranties shall exist for 24 months or unlimited miles. Warranty term begins the day the engine ships (NOT INSTALL DATE). Engines used in marine applications that are not cataloged as such carry no warranty whatsoever. Marine Engines Carry an 18 Month Unlimited Hour Warranty. Please refer to www.atkvege.com for detailed Marine Engine Warranty Documentation.

    Standards: Subject to the limitations listed herein. ATK, at its option, shall repair or replace a product within the warranty term after determination by ATK that the product is defective due to parts and/or workmanship. All products are to be returned to ATK for inspection. Products not returned to ATK will not be warranted. All repairs and/or replacements covered by this warranty must be authorized by ATK. Unauthorized repairs will not be paid.

    Limitations: This warranty applies to products originally supplied by ATK. This warranty does not apply to or include any of the following:

    1. Any product used for competition, racing or related purposes.
    2. Damage as a result to installer error.
    3. Damage resulting from OVERHEATING, LACK OF LUBRICATION, or CONTAMINATION.
    4. Damage resulting from PRE-IGNITION or DETONATION. This includes but is not limited to: melted or broken piston, broken piston rings, damaged cylinder heads, leaking head gaskets, etc.
    5. Foreign objects entering the cylinder creating damage to pistons, cylinder walls, etc.
    6. Broken crankshafts, broken connecting rods, broken or damaged piston rings, broken valve train resulting from excessive R.P.M.
    7. A crankshaft thrust surface that is worn due to excessive forward pressure placed on the rear of the crankshaft.
    8. Repair or replacement required as a result of any accident or misuse.
    9. Repair or replacement of any accessory or service item, including specifically but not limited to: all components of the cooling, fuel, electrical, and ignition systems including belts, hoses, and filters.
    10. Replacement of any aftermarket part used in the engine. ATK is not responsible for defective parts supplied by aftermarket companies that may have been used in the build process such as (Distributors, Carburetors, Lifters/Valve Train, Water Pumps, Fuel Pumps, and Oil Pumps etc.) Most of the parts will carry there own warranty through the proper vendor. When an engine is purchased with the optional Dyno Test and Tune session we are able diagnose a defective part at that time and will change it out until the problem no longer occurs. This will not insure a part is not defective and premature failure can still arise after the engine has left our facility.

    Disclaimers:

    1. Applications are not verified and are not legal for pollution controlled vehicles. Computer controlled vehicles may need updated ECM, Chips, Fuel Systems, Etc. Please verify application before ordering.
    2. HP/TQ Measurements vary slightly from engine to engine. Accordingly, power measurements are typically within +/- 3% on our dyno (your dyno sheets).
    3. ATK Reserves the right to substitute parts or change specifications on all products offered.
    4. All images are for illustrative purposes only. Actual engine may vary in color, dress level and components used.

    Limited Liability:
    ATK’s liability under this warranty is limited solely to the repair or replacement of defective product. ATK shall not be liable for any incidental, special, consequential or exemplary damages including but not limited to freight charges, rental cars, towing fees or for any service not expressly provided for herein, relating or arising from the ATK product.

    Limited Warranty:
    This warranty is given in lieu of all other warranties, expressed or implied, including any warranty of merchantability, or fitness for a particular purpose, on the part of ATK or the dealer installing the engine. No dealer nor any agent or employee thereof, is authorized to extend or modify this warranty.

    Governing Law and Venue:
    The terms and provisions of this Limited Warranty shall be governed by and construed according to the laws of the State of Illinois, without reference to its rules relating to the choice of law provisions. Any action at law, suit in equity or judicial proceeding for the enforcement of this Limited Warranty or any provision thereof shall be brought exclusively before the United States District Court for the Northern District of Illinois or any state court sitting in Cook County, Illinois.

    Labor for Stage I, II, and III Warranty:
    ATK authorized repairs will be compensated at a rate not to exceed the Mitchell Repair Manual’s published applicable flat rate schedule. As of January 1st, 2024, the Hourly rates for all authorized labor claims will be paid in accordance with the original installation rate, not to exceed $95.00 per flat rate hour per Mitchell book time or comparable application. ATK does not pay extra hours due to the type of vehicle or extra work needed due to customization, show cars, etc. Do-it-yourself install/repairs and repairs performed by unlicensed repair facilities DO NOT qualify for labor reimbursements.

    Additional Owner/User Obligations:
    Initial Startup: Initial Startup: Valves must be re-adjusted to manufacturer’s specifications. Due to various component designs, cylinder head re-torque may or may not be required in your particular application. Refer to factory shop manual for the proper procedure for your engine type. If for any reason you are unsure what action to take, please contact our customer service department via our toll free number at 800-421-3746. First service between 600-1000 miles after installation: Oil and filter must be changed, valves re-adjusted and cylinder heads re-torqued (refer to initial startup instructions). Failures to perform these basic operations may result in a voided warranty.

    *Not legal for sale or use on any pollution controlled vehicle*

    Speedway Motors 91607096 Specifications

    KEY SPECS
    MFG. Part #91607096
    BrandSpeedway Motors
    Crate Engine TypeDeluxe Crate Engine
    Engine Displacement323 cu. in.
    Horsepower475 horsepower
    Compression Ratio9.9:1
    Torque430 ft./lbs.
    Camshaft TypeHydraulic Roller
    Cylinder Head MaterialAluminum
    Piston MaterialHypereutectic Aluminum
    Crankshaft MaterialNodular Iron
    Combustion Chamber Volume65cc
    Camshaft Duration (.050 in)223° intake / 231° exhaust
    Camshaft Lift (in).533 Intake / .554 Exhaust
    Bore x Stroke (in)3.780" x 3.622"
    Carburetor IncludedNo
    Intake Manifold IncludedYes
    Distributor IncludedNo
    Connecting Rod MaterialOEM Style
    Valve Covers IncludedYes
    Engine BalanceInternal
    Cylinder Heads IncludedYes
    Rear Main Seal Style1-piece
    Throttle Body IncludedYes
    Oil Pan IncludedNo
    Timing Cover IncludedYes
    Water Pump IncludedNo
    Harmonic Balancer IncludedNo
    Flexplate IncludedNo
    Flywheel IncludedNo
    Air Cleaner IncludedNo
    Spark Plugs IncludedNo
    Spark Plug Wires IncludedNo
    Computer IncludedNo
    Wiring Harness IncludedNo
    Spark Plug StyleStock

    Fitment

    • GM LC9

    • GM LC9

    • GM LC9

    • GM LH6

    • GM LC9

    • GM LC9

    Customer Impersonation Script