The LS5 (above engine statistics) was joined by the LS6 (below) for 1971, both as the top horsepower big block options.
The future had arrived in the form of lower compression ratios for 1971. Unleaded gasoline and its lower octane rating forced the move and an era was over, not to return. The change caused the horsepower ratings of the LS5 motor to go from 390 horsepower via a 10.25:1 compression ration (1970) to 365 horsepower and a 8.5:1 compression ratio. Most reports indicate the performance loss was negligible and gasoline purchasing was easier.
1971 was the last year for the fiber optic light monitoring system located behind the shifter.
Above: Famous Car and Driver "Bragging" magazine advertisement. Below: 1971 sales brochure cover.
