COVID-19 UPDATE: We’re here for you and shipping fast, prioritizing health and safety first. Learn More

ATK Chevy LS2 403CI Stroker Short Block -15cc Dished Pistons 58 Tooth SP86 Engine

Item #22736

ATK Chevy LS2 403CI Stroker Short Block -15cc Dished Pistons 58 Tooth SP86 Engine
ATK SP86 Chevy LS2 403CI Stroker Short Block -15cc
- +
Quantity: close

In stock

< Back


Made for naturally aspirated engines, the ATK SP86 Chevy LS2 403CI Stroker Short Block has tremendous strength to handle huge power. This short block is assembled with new GM LS2 aluminum block, internally balanced forged crankshaft, forged connecting rods, forged pistons, and sealed freeze plugs for reliable operation.

Engine Specifications:

  • Block: New GM LS2 Aluminum
  • Bore/Stroke: 4.005 x 4.000
  • Displacement: 403 C.I.D.
  • Crankshaft: K1 4340 Forged 4.000" Stroke Internally Balanced
  • Connecting Rods: K1 4340 Forged H Beam with ARP 2000 Bolts
  • Pistons: Wiseco 2618 Forged -15cc Dished
  • 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

More info...


ATK High Performance Chevy LS2 403 Stroker 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 #689-10296 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.

Eastwood Offers Free Lifetime Technical Support

Click here for product SDS information

Attention California Residents - Proposition 65

Proposition 65 Warning WARNING - Cancer and Reproductive Harm -

Customer Reviews

Questions & Answers