High Performance Short Block GM LS 5.3/5.7

Name: High Performance Short Block GM LS 5.3/5.7
Brand: ATK ENGINES
SKU: 059-SP76
Price: 3393.09 USD
Availability: InStock

^$3,393⁰⁹

Core Charge: ^$285⁰⁰

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Ships on Dec 01, 2026

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Gen III/IV LS 24 Tooth

High Performance Short Block

GM LS 5.3/5.7 347ci

Cast Iron 5.3L LM7 Block Bored to 5.7L

OE Reground .010"/.010" Crankshaft 24 Tooth

4340 Forged I Beam Rods

2618 Forged Dish Pistons -11cc

This short block is built for naturally aspirated engines up to 700hp.

Block Information:

Seasoned OE 1999-2007 GM LM7 5.3L
Bore/Stroke: 3.903" x 3.622"
Displacement: 347ci
Camshaft Bearings: Installed and clocked to OEM position
Freeze Plugs: Installed and sealed
Oil Galley Plugs: Installed and sealed

Rotating Assembly:

Crankshaft: OE reground .010"/.010" 24 tooth reluctor wheel
Rods: Scat Pro 4340 Forged I Beam Rods with ARP 8740 bolts
Compression Ratio: 65cc= 9.5:1 67cc= 9.3:1 / 70cc= 8.9:1
Pistons: Wiseco 2618 Forged dished -11cc
Rings: Wiseco GFX (alloy steel top ring)

Recommended Components:

Balancer: Internal balance
Flexplate/Flywheel: Internal balance
Head Gasket: .051" thickness or per application
Oil: 10W40 Non synthetic for first 3000 miles
Oil Filter: Wix or K&N per application
Oil Pump: Melling #689-10295 with high pressure spring

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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Please CLICK HERE for ATK Warranty

Short Blocks for Street or Strip

ATK Engines High-Performance Short Blocks provide the foundation for your next engine build for Gen I Small Block Chevys, Big Block Chevys, and Gen III/IV LS. These short blocks support mild to extreme horsepower in naturally aspirated or boosted applications.

Part TypeShort Block

Product LineATK Engines Small, Big Block Chevy & LS Short Blocks

BrandATK ENGINES

Package Height26.0

Package Width26.0

Package Length29.0

Weight260.0 PG

Part CategoryPerformance Parts

QuantitySold individually

Part FitmentSemi Universal

Vendor Part NumberSP76

Package Qty1