ATK Chevy LM7 383CI Short Block -15cc Dished Pistons 24 Tooth SP78 Engine

Item #22728

Made in the USA
ATK Chevy LM7 383CI Short Block -15cc Dished Pistons 24 Tooth SP78 Engine
SP78 ATK Chevy LM7 383CI Short Block -15cc Dished Pistons 24 Tooth
* ** 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.
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Dominate the streets and strips with sheer power by installing this ATK SP78 Chevy LM7 383CI Short Block. It is designed for naturally aspirated engines of up to 700 horsepower, making it suitable for hardcore rides. The short block is internally balanced and comes with premium-quality forged parts to deliver reliable performance.

Engine Specifications:

  • Block: GM LM7 5.3L
  • Bore/Stroke: 3.903 x 4.000
  • Displacement: 383CI.
  • Crankshaft: K1 4340 Forged 4.000" Internally Balanced 24 Tooth
  • Connecting Rods: Scat Premium Pro 4340 Forged I Beam 6.125" ARP 8740 Bolts
  • Pistons: Wiseco 2618 Forged -15cc Dished - Coated Skirts
  • Piston Rings: Wiseco GFX (Alloy Steel top ring)
  • Camshaft Bearings: Installed & Clocked to OEM Position
  • Freeze Plugs: Brass Installed & Sealed
  • Oil Galley Plugs: Installed & Sealed
  • Weight: 285

Every great build needs a solid foundation! For that reason, we take the hard work out of the picture by selling short blocks that are ready for you to complete yourself. Our GM Short Blocks are most commonly packaged as the engine block assembled with Pistons, Piston Rings and Crankshaft installed.

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 High Performance Chevy LM7 383 Short Blocks


Engine Information:

• Oil: 5W30
• Harmonic Balancer/Damper: Internally Balanced
• Flex Plate / Flywheel: Internally Balanced


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

Disclaimer: The parts listed are ATK’s recommendations of parts to be used to obtain our power figures listed. Power figures can vary based on parts used by the end user. It is the customer’s responsibility to verify components will work for their application. Some modifications to the vehicle may be required using these and or other aftermarket parts.

Shipping Instructions

Shipping is free and lift gate will be provided.

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