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GM 5.5 Liter LT7 Twin-Turbo V8 Engine

The GM twin-turbocharged 5.5L V8 LT7 gasoline engine is the Detroit-based automaker’s most powerful production-spec powerplant ever manufactured, and was unveiled alongside the 2025 Corvette ZR1.

Overview

Debuting as the centerpiece of the Corvette C8 ZR1, the twin-turbocharged 5.5L V8 LT7 gasoline engine is based on the naturally aspirated 5.5L V8 LT6 gasoline engine found in the Corvette C8 Z06. In fact, the two powerplants were developed in tandem with one another. However, General Motors engineers claimed that the 5.5L LT7 was not just an “LT6 build for boost”, but rather optimized for a boosted application.

It’s worth noting that despite widespread expectations for a transition to a cross-plane crank, the 5.5L LT7 retained the 5.5L LT6’s signature flat-plane crank.

5.5L V8 LT7.

5.5L V8 LT7

As the first production-spec turbocharged engine ever fit into a Chevrolet Corvette, the 5.5L LT7 carried many firsts and featured a laundry list of upgrades to handle its lofty output figures, including:

  • Additional block and head machining
  • Counterweight changes
  • Secondary port fuel injection system
  • Head castings with unique ports and a larger combustion chamber
  • Valvetrain timing and lift profile optimization
  • All-new intake system
  • CNC-machined combustion chamber, exhaust and intake ports
  • Dual, ported shroud, ball bearing, mono-scroll 76-mm turbochargers
  • Anti-lag calibration techniques
5.5L V8 LT7.

5.5L V8 LT7

Vehicle Applications

Model Year(s) Application Transmission Horsepower @ RPM Torque @ RPM
2025 – Present Corvette ZR1 Eight-Speed Dual Clutch Auto 1064 @ 7000 828 @ 6000
- Corvette Zora - - -

Specifications

GM 5.5L V8 LT7 Engine Specs
Type 5.5L V8
GM RPO Code LT7
Displacement 5.5L
Compression Ratio 9.8:1
Valvetrain Dual-Overhead Camshafts, Four-Valves Per Cylinder, Flat-Plane Crank
Valves Per Cylinder Four
Block Material Sand-Cast Aluminum
Cylinder Head Material Aluminum
Firing Order 1-4-3-8-7-6-5-2
Bore x Stroke (in. / mm) 4.104 / 104.25 x 3.1 / 80
Aspiration Twin-Turbocharged
Fuel Delivery PDI (Direct And Port Injection)
Ignition System Direct Coil-on-Plug

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News

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