09/30/2026
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Chief engineer Dustin Gardner described the testing: twelve-foot exhaust pipes glowing red from the test cell to the wall, cracked emissions handling stacks, and one engine that in his words freed itself from the shackles of the dyno.
The existing setup could not contain 1,064 horsepower.
That is what the ZR1's LT7 makes, twin-turbocharged, from 5.5 litres. The most powerful V8 any American manufacturer has ever put in a production car.
What makes it interesting is that it was never a modified version of anything.
Chevrolet calls the architecture Gemini, because the LT6 and the LT7 were designed at the same time as twins. Same block casting, same bore spacing, same flat-plane crankshaft concept, and then two completely divergent paths from there.
The naturally aspirated LT6 in the Z06 makes 670 horsepower at 8,600 RPM. The LT7 makes its power at 7,000 with 24 psi of boost.
The compression tells you how differently they were tuned. The LT6 runs 12.5:1. The LT7 runs 9.8:1, because the turbochargers supply the cylinder pressure that compression provides in a naturally aspirated engine, and the lower ratio leaves headroom before detonation under boost.
Eight hundred lb-ft is available from 3,000 RPM, which means four-digit horsepower and near-peak torque across a 5,000 RPM window.
The materials are where the engineering shows. Turbine wheels in MAR-M246, a nickel superalloy rated to 1,900 degrees Fahrenheit and more heat resistant than the Inconel normally used. Titanium intake valves. Sodium-filled Nimonic exhaust valves. Seven-stage dry sump oiling with jets spraying the underside of each piston to pull heat out of the crown.
And direct injection at over 5,000 psi, with a supplementary port injection system that activates at wide-open throttle because the direct injectors alone cannot deliver enough fuel at full boost.
The exhaust moves so much gas that the quad outlets generate 37 pounds of measurable thrust.