$400 Off

ATK SMIHP5.3 GM 5.3L LM7 LS Vortec Long Block Engine, 385 HP

$400 Off

ATK SMIHP5.3 GM 5.3L LM7 LS Vortec Long Block Engine, 385 HP
ATK Engines

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#35021053

ATK SMIHP5.3 GM 5.3L LM7 LS Vortec Long Block Engine, 385 HP

  • Makes 385+ HP and 390+ lb-ft torque, a major upgrade over the stock 5.3L LM7
  • Remanufactured seasoned LM7 iron block with OEM GM crank, 24-tooth reluctor, and rods
  • Hypereutectic 9.5:1 pistons with moly rings for 91 octane pump-gas reliability
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$4,199.99

/each

On Backorder

$4,599.99

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This part is Backordered. We estimate this item will ship on or before November 15th.


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Product Summary

Long Block Crate Engine Type, 9.5:1 Compression Ratio

  • Makes 385+ HP and 390+ lb-ft torque, a major upgrade over the stock 5.3L LM7
  • Remanufactured seasoned LM7 iron block with OEM GM crank, 24-tooth reluctor, and rods
  • Hypereutectic 9.5:1 pistons with moly rings for 91 octane pump-gas reliability
  • Custom hydraulic roller cam for strong mid to upper RPM power and noticeable idle
  • Direct fit for 1999-2007 Chevy LM7 trucks or LS swaps; dyno tune required
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Key Specs

Crate Engine TypeLong Block
Compression Ratio9.5:1
Engine Displacement5.3L
Camshaft TypeHydraulic Roller
Cylinder Head MaterialAluminum
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ATK Engines SMIIHP5.3 Details

Ready to wake up a tired 5.3L truck or build a stout, budget-friendly LS swap for your hot rod? The ATK High Performance SMIHP5.3 5.3L long block delivers a serious step up over stock, making 385+ horsepower and 390+ lb-ft of torque. It is built as a direct performance upgrade for 1999-2007 Chevy trucks with the LM7 5.3L, and it is equally at home in an LS-swapped street rod, muscle car, or truck.

This remanufactured engine starts with a seasoned OE LM7 iron block, so internal stresses are already relieved for stable, long-lasting bore geometry. Inside, the internally balanced OEM GM 3.622 in. stroke crank with 24-tooth reluctor wheel and OE GM forged powdered metal rods are paired with hypereutectic dish pistons at 9.5:1 compression and moly rings for strength and pump-gas friendly reliability. A custom-ground hydraulic roller camshaft brings big mid-range and upper-RPM power along with a noticeable, aggressive idle. OE aluminum cylinder heads with 61.15cc chambers, 1.89 in. intake and 1.55 in. exhaust valves, and 1.7 ratio rockers finish off the top end. Cam bearings are installed and clocked to the OEM position, and brass freeze plugs and oil galley plugs are installed and sealed. Cam specs are included with the engine.

Engine Specifications:

  • Horsepower: 385+
  • Torque: 390+ lb-ft
  • Displacement: 5.3L (325 ci)
  • Bore x Stroke: Up to 3.809 in. x 3.622 in.
  • Block: Seasoned OE LM7 5.3L cast iron
  • Crankshaft: OEM GM, 3.622 in. stroke, internally balanced, 24-tooth reluctor wheel, .857 in. flange
  • Connecting Rods: OE GM forged powdered metal, 6.098 in., stock bolts
  • Pistons: Hypereutectic dish, 9.5:1 compression
  • Rings: Moly
  • Camshaft: Hydraulic roller, custom performance grind (specs included with engine)
  • Cam Bearings: Installed and clocked to OEM position
  • Cylinder Heads: OE aluminum, 61.15cc chambers, 1.89 in./1.55 in. valves
  • Rocker Arms: OE powdered metal, 1.7 ratio
  • Freeze Plugs: Brass, installed and sealed
  • Oil Galley Plugs: Installed and sealed
  • Rear Main Seal: 1-piece
  • Balance: Internal
  • Weight: 385 lbs.

Not Included: Intake manifold, throttle body, oil pan, valve covers, timing cover, water pump, harmonic balancer, flexplate/flywheel, spark plugs, plug wires, computer, and wiring harness.

Recommended Components:

  • Oil: 5W-30
  • Fuel System: OE EFI system with upgraded injectors
  • Intake: Stock car-style fuel-injected intake (truck intakes will make less power)
  • Harmonic Balancer: Stock, internally balanced
  • Flexplate/Flywheel: Stock, internally balanced
  • Spark Plugs: Stock, gapped at .035 in.
  • Ignition Timing: Factory specification via PCM (tune required)
  • Firing Order: Stock
  • Fuel: 91 octane minimum
  • Torque Converter: Stock or 1,800 RPM stall
  • Exhaust: 1-5/8 in. or 1-3/4 in. primary tube headers

ATK Engines SMIIHP5.3 Specifications

KEY SPECS
MFG. Part #SMIIHP5.3
BrandATK Engines
Crate Engine TypeLong Block
Compression Ratio9.5:1
Engine Displacement5.3L
Camshaft TypeHydraulic Roller
Cylinder Head MaterialAluminum
Piston MaterialHypereutectic Aluminum
Crankshaft MaterialCast Iron
Carburetor IncludedNo
Intake Manifold IncludedNo
Distributor IncludedNo
Connecting Rod MaterialPowdered Metal
Valve Covers IncludedNo
Engine BalanceInternal
Cylinder Heads IncludedYes
Rear Main Seal Style1-piece
Throttle Body IncludedNo
Timing Cover IncludedNo
Oil Pan IncludedNo
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
Reluctor Wheel24x
GENERAL
Head Gaskets IncludedYes
Camshaft IncludedYes
GTIN Code00653517137211
Sold in QuantityEach

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Fitment

  • GM LM4

  • GM LS6

  • GM LS2

  • GM LSA

  • GM LM7

  • GM LQ9

  • 6.2 Chevy LS V8

  • GM L9H

  • GM L94

  • GM LM7

  • GM LQ9

  • 6.2 Chevy LS V8

  • GM L9H

  • GM L94

  • GM LM7

  • GM LQ9

  • 6.2 Chevy LS V8

  • GM L9H

  • GM L76

  • GM LC9

  • GM LMG

  • GM LY5

  • GM LY5

  • GM LM7

  • 4.8 Chevy LS V8

  • GM LM7

  • GM LQ4

  • GM LS1

  • GM LS3

  • GM LS1

  • GM LS1

  • GM LS6

  • GM LS2

  • GM LS3

  • GM LS4

  • GM LS4

  • 4.8 Chevy LS V8

  • GM LM7

  • 4.8 Chevy LS V8

  • GM L20

  • GM LM7

  • GM LY2

  • 4.8 Chevy LS V8

  • GM LM7

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ9

  • GM LQ4

  • GM L98

  • GM LM7

  • GM LQ4

  • GM L98

  • GM LQ9

  • GM L98

  • GM LQ4

  • GM L98

  • GM LQ4

  • GM LQ4

  • GM L98

  • GM L98

  • GM LQ4

  • GM LQ4

  • GM L98

  • GM LZ1

  • GM LS3

  • GM LM4

  • GM L77

  • GM LMG

  • GM LY5

  • GM LM7

  • GM L59

  • GM LM7

  • GM LC9

  • GM LMG

  • GM LY5

  • GM LC9

  • GM LMG

  • GM LMG

  • GM LY5

  • GM LQ4

  • GM L96

  • GM LMG

  • GM LY5

  • 4.8 Chevy LS V8

  • GM L59

  • GM LM7

  • 4.8 Chevy LS V8

  • GM LMG

  • GM LY5

  • 6.2 Chevy LS V8

  • GM L9H

  • GM LC9

  • GM LMG

  • GM LZ1

  • GM L9H

  • GM LC9

  • GM LMG

  • GM LZ1

  • GM LC9

  • GM LMG

  • GM LZ1

  • GM LMG

  • GM LY5

  • GM LH6

  • GM LS2

  • GM LM4

  • GM LM4

  • GM LM4

  • 4.8 Chevy LS V8

  • GM LM7

  • GM LQ4

  • 4.8 Chevy LS V8

  • GM L33

  • GM L94

  • GM LM7

  • GM LQ4

  • 4.8 Chevy LS V8

  • GM L33

  • GM L94

  • GM LQ4

  • 4.8 Chevy LS V8

  • GM LM7

  • GM LQ4

  • 4.8 Chevy LS V8

  • GM L33

  • GM L94

  • GM LQ4

  • 4.8 Chevy LS V8

  • GM LM7

  • GM LQ4

  • 4.8 Chevy LS V8

  • GM L33

  • GM L94

  • GM LQ4

  • GM L20

  • GM L9H

  • GM LC9

  • GM LMG

  • GM LZ1

  • GM L33

  • GM L59

  • GM LM7

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LM7

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM L96

  • GM LQ4

  • GM LQ4

  • GM L96

  • GM LQ4

  • GM L96

  • GM L96

  • GM LQ4

  • 4.8 Chevy LS V8

  • GM L20

  • GM LM7

  • GM LY2

  • 4.8 Chevy LS V8

  • GM L20

  • GM L94

  • GM LM7

  • GM LY2

  • GM LZ1

  • GM L94

  • GM LC9

  • GM LMG

  • GM LZ1

  • GM LM7

  • GM L59

  • GM LM7

  • GM LQ4

  • GM L96

  • GM LQ4

  • GM L96

  • GM LQ4

  • 6.2 Chevy LS V8

  • GM LH8

  • GM LH9

  • GM LH8

  • GM LH9

  • GM LS1

  • GM LS3

  • GM LS1

  • GM LS2

Customer Impersonation Script