427ci LSx Boosted Competition Short Block


The LSx 427ci competition short block uses a new Dart SHP Pro cast iron block with 4.125″ bore to produce the 427ci.

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Grand total


  • New Dart SHP Pro LS Block Honed with Torque Plates
  • Bore Size 4.130″
  • Resurfaced to Match Pistons
  • Line Honed with ARP Main Studs
  • Blueprinted Oil Clearances
  • All New GM Block Plugs Installed
  • New Durabond Cam Bearings Installed


  • Wiseco Custom Forged Boost Pistons


  • King H-Series Main and Rod Bearings


  • Callies Comp Star 4340 Forged Steel 8 Counterweight
  • Stroke 4.000”
  • Your Choice of 24x or 58x Reluctor Wheel (Billet 24X Reluctor Wheel is an Extra $150″)
  • Internally Balanced Front and Rear


  • Callies Comp Star Extreme 4340 Forged Steel H-Beam
  • 6.125” Length
  • ARP 2000 Rod Bolts


Technical Links: (Coming Soon)


  • Installing Windage Tray, Oil Pump Pick Up and Covers
  • Installing LS Harmonic Balancer
  • Torque Specs for Entire Engine
  • How to Set Pushrod Preload on LS Engine
  • How to Properly Prime the LS Oil Pump
  • Recommendations; Oil, filter, spark plugs


Hey there, power seekers! Get ready to be blown away by the Golen Engine 427ci LSx Boosted Competition Short Block. This engine is a true marvel for those who crave serious horsepower. We’re talking a build that can handle up to an astonishing 1000hp. At its heart lies a robust base, ready for the toughest of boosts, with ARP main studs and top-notch cam bearings.

Featuring a Callies Comp Star 4340 forged steel crankshaft and H-Beam rods, reinforced with ARP 2000 rod bolts, this engine is designed to withstand extreme power. The use of Wiseco 2618 forged pistons and GFX ring sets makes it ideal for high-pressure boosted environments.

Fully balanced and blueprinted, and assembled with King bearings, this engine is fine-tuned for peak performance under any condition. It’s engineered to handle boosts up to 20 psi effortlessly, be it from superchargers or turbos.

Need to complete your monster build? We offer everything, from Cometic MLS head gaskets to ARP Head studs, and our Golen Engine Aftermarket LS3 CNC Ported heads with thick decks, perfect for sealing in that boost.

And don’t sweat the assembly – we’ve got full tech support, plus a wealth of tech links and videos for those off-hours queries. The Golen Engine 427ci LSx Boosted Competition Short Block isn’t just an engine; it’s a ticket to a 1000hp journey. Let’s build that dream machine!

Additional information

Weight 350 lbs
Dimensions 38 × 26 × 27 in