The Chevrolet 454 in the 1970 LS6 configuration is frequently called the greatest factory muscle car engine ever built, and the argument is difficult to counter. The combination of displacement, compression ratio, induction, and valvetrain produced a street engine that could be driven to a drag strip and run 13-second quarter miles without preparation.

The LS5 454 offered in the same year was a milder tune — lower compression, hydraulic lifters — and made a stated 360 horsepower. The LS6 was the maximum version: solid lifters, four-bolt main caps, aluminum intake, 800 CFM Holley, 11.25:1 compression.

The gap between 1970 and 1971 in terms of factory-available performance is almost exactly the gap between the LS6 and the subsequent year's detuned 454. The LS6 was the end of something.