Precision LS3 Engine Build: Inside the Heart of the Chevy Impala Project

Precision LS3 Engine Build: Inside the Heart of the Chevy Impala Project

At Precision Performance, we specialize in building engines that deliver more than just horsepower they deliver confidence. Our latest LS3 build for a Chevy Impala is a showcase of modern GM engineering, upgraded for street performance, reliability, and future scalability.

This article dives deep into the LS3 platform, the specific upgrades we performed, and the broader possibilities for enthusiasts looking to build their own LS-powered machine.

What Is the LS3 Engine?

The GM LS3 is a 6.2L Gen IV small-block V8, originally introduced in the 2008 Corvette and later used in Camaros, G8s, and performance swaps. It’s known for its:

  • Aluminum block and heads
  • High-flow rectangular port heads
  • Factory output of 430–436 hp
  • Strong bottom end and high RPM capability

Its combination of displacement, airflow, and aftermarket support makes it one of the most popular LS variants for street and track builds.

Precision Performance LS3 Build Specs

This build was designed for naturally aspirated street performance with room to grow. Here’s what went into it:

Bottom End

  • Pistons: 2618 forged aluminum for high strength and thermal stability
  • Piston Rings: File-fit moly rings for tight sealing
  • Rod Bolts: ARP 2000 fasteners for high-RPM durability
  • Bearings: Clevite H-series performance bearings
  • Compression Ratio: ~10.7:1

Camshaft & Valvetrain

  • Camshaft Type: Hydraulic roller
  • Duration @ .050": 229° intake / 244° exhaust
  • Lift: .615" intake / .595" exhaust
  • Lobe Separation Angle: 112°
  • Valve Springs: Dual-beehive springs rated for 6500+ RPM
  • Retainers: Titanium
  • Rocker Arms: Trunnion upgrade kit with captured bearings
  • Pushrods: Chromoly 7.400” length, .080” wall thickness

This cam profile delivers a lopey idle, strong mid-range torque, and excellent top-end power-perfect for spirited street driving.

 Induction & Fuel System

  • Intake Manifold: OEM LS3
  • Throttle Body: 90mm drive-by-wire
  • Fuel Injectors: 42 lb/hr high-flow
  • Fuel Pump: Walbro 255 LPH in-tank
  • Fuel Rails: OEM LS3 with AN fittings
  • Regulator: Return-style adjustable

Engine Management

  • ECU: GM E38
  • Tuning Software: HP Tuners
  • Calibration: Custom dyno tune for ignition timing, fuel trims, cam advance, and knock sensor sensitivity

Popular LS3 Upgrade Paths

The LS3 is a flexible platform that supports a wide range of upgrades depending on your goals:

For Naturally Aspirated Builds

  • CNC ported heads
  • Larger throttle bodies (102mm)
  • High-rise intake manifolds
  • More aggressive cam profiles

For Forced Induction

  • Turbo or supercharger kits
  • Lower compression forged pistons
  • Boost-ready fuel systems
  • Intercoolers and meth injection

Supporting Mods

  • Stroker kits (to 416 or 427 cu in)
  • Standalone ECUs (Holley, Haltech)
  • Upgraded ignition coils and wires
  • Long-tube headers and performance exhaust

Whether you’re building for street, strip, or track, the LS3 can be tailored to meet your performance goals.

Download the Full Spec Sheet

Want a detailed breakdown of this build?
Download the LS3 Engine Spec Sheet (PDF)

Ready to Build Your Own LS Monster?

At Precision Performance, we offer:

  • Engine blueprinting and assembly
  • Performance consultation

Contact us today to start your custom LS build.

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