SKU: BLS4273K4L7
BluePrint Engines GM LS Compatible 427 c.i. Engine and 4L65/70E Automatic Transmission - Standard Edition Builder Series - Natural Pulley Kit - Holley Terminator X EFI System
$26,249.00
427 c.i. 605 Horsepower Builder Series

Horsepower & Torque: 605 Horsepower / 565 ft. lbs. Torque

Cylinder Heads: BluePrint Engines Aluminum Cylinder Heads

Compression Ratio: 11:1

Camshaft: Hydraulic Roller Cam - .624 Intake / .624 Exhaust Lift and 239 Intake / 255 Exhaust Duration @ .050 – 114 LSA

Pistons: Forged

Crankshaft: Forged Crank – 4.125" Stroke and Forged 6.125" Rods

Fuel Injection: Holley Terminator X Max - Gen IV Complete ECU/Harness EFI System

Fuel Recommendation: 91+ Octane

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Financing available at checkout with Affirm

Overview:

BluePrint’s LS-compatible 427 c.i. Builder Series package delivers big-inch torque with modern drivability, paired seamlessly to a 4L65/70E automatic transmission for a ready-to-run upgrade. This standard edition setup includes BluePrint’s dyno-verified 427, engineered for serious street performance with rock-solid reliability, all managed by the Holley Terminator X EFI system for crisp throttle response and easy tuning. Finished with a natural pulley kit for a clean, functional look, this combo is built to drop in, hook up, and transform your build with the power and refinement of a modern LS powerhouse.

Description:

  • Horsepower & Torque: 605 Horsepower / 565 ft. lbs. Torque
  • Compression Ratio: 11:1
  • BluePrint Engines LS3 Aluminum Heads
  • BluePrint Engines Hydraulic Roller Cam
  • BluePrint Engines Forged Crank
  • BluePrint Engines Forged Pistons

Block:

  • BluePrint Engines High Strength Cast Iron (LSX Style) Block
  • Increased Deck Thickness and Strength Webbing
  • Utilizes OEM LS3 Front and Rear Covers
  • Improved Water Jacket Design
  • Extended Cylinder Skirt
  • 1-Piece Rear Main Seal
  • Priority Main Oiling
  • 4.0665" Bore
  • 6-Bolt Main

Rotating Assembly:

  • Forged Crankshaft
  • 4.125" stroke
  • Forged 6.125" Connecting Rods w/ 150,000 PSI Bolts
  • Forged Pistons
  • Internally Balanced Front and Rear

Cylinder Heads:

  • BluePrint Aluminum Cylinder Heads - PS8015
  • 70cc Chamber
  • 2.165" Intake - 1.600" Exhaust Valves
  • 259cc Intake - 102cc Exhaust Runners

Cam Specs:

  • Hydraulic Roller Cam
  • .624 Intake - .624 Exhaust Lift
  • 239 Intake - 255 Exhaust Duration
  • @.050-114 Degree Lobe Separation

Holley Terminator X Max Specific Features and Benefits:

  • Real Time Fuel Map Learning Simplifies Tuning by Dynamically Adjusting the Base Fuel Rate
  • On Board Bosch LSU 4.9 Wideband Control, Enabling Accurate AFR Readings and Closed Loop Tuning
  • Eight High Impedance Injector Drivers, Ideal for Stock LS Injectors and Holley EFI Injectors
  • Integrated 1-Bar MAP Sensor for Naturally Aspirated or Nitrous Setups, with Harness Support for External Higher Bar Sensors if needed
  • 4 Configurable Inputs (12V, Ground, 5V, Frequency) and 2 Outputs (Ground, PWM) - Ideal for Electric Fans, Boost Control Solenoids, Nitrous Control and more
  • Free PC Tuning Software via USB/CAN Interface for Full Laptop Control and Advance Setup
  • Integrated 3.5" Touchscreen Handheld with Setup Wizard, Internal Data Logging, and Real Time Gauge Displays
  • Terminator X Max ECU will Include a Base Timing Map Pre-Configured for this engine

Also Includes:

  • LS Swap Oil Pan - Windage Tray - Pick Up Screen
  • BluePrint Engines Fuel Injectors and Rail
  • DBW Throttle Body - BPP12191019
  • Throttle Pedal, and Sensors
  • GM Plastic Intake Manifold
  • Spark Plugs & Wires
  • Harmonic Balancer
  • Coil Packs 
  • Natural Front Accessory Drive:
    • LT1 Style 150-amp Alternator
    • LT1 Style Water Pump
    • Type II Power Steering Pump
    • Compact Style Air Conditioner Compressor

Assembled with Complete Performance Built 4l65/70e Four Speed Automatic Transmission Package:

  • 4L65/70E Complete Package
    • (1996-2008 13-Pin Harness)
  • Electronic Transmission Controller Included
  • 2200-2400 Stall Torque Converter
  • Flex Plate
  • Starter
    • First Gear Ratio: 3.059:1
    • Second Gear Ratio: 1.625:1
    • Third Gear Ratio: 1.000:1
    • Fourth Gear Ratio: 0.696:1

Notes:

  • This Holley EFI Equipped engine has a fully calibrated ECU by BluePrint Engines. Please DO NOT follow the Holley EFI manual for the calibration of the ECU.
  • Retro fit oil pan will fit most 1955-1995 GM front engine, RWD, V8 cars
    Not for use in pollution-controlled vehicles or in dry sump applications.
  • BluePrint Engines Recommends Air Intake Kit BPPLS01013 to ensure correct MAF calculations and Dyno calibration are maintained with the provided ECU / tuning.
  • Engine/Trans Package Ships assembled.

WARNING: Cancer and Reproductive Harm
Bragging Rights Included.

EVERY BLUEPRINT ENGINE ACES THE DYNO TEST

We make sure we hit our target horsepower and proper torque with every crate engine. We use an advanced computerized balancer in our in-house dyno testing rooms to get our rotating assemblies within two grams, ensuring silky smooth power over the entire RPM range. That’s precisely why our engines sound and run better than our competitors.

All specs, zero speculation: A comprehensive, dyno-generated printout showing your critical engine specs will accompany your delivered engine — every time. No more guessing or wondering what your installed engine’s real-world peak horsepower and torque ratings actually are. Any doubters in the crowd? Simply flash ‘em your exact engine’s dyno results.

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