Chevrolet LT-1

The LT-1 is a Chevrolet small-block engine produced by the Chevrolet division of General Motors between 1970 and 1972. It was available exclusively in the Corvette and Camaro and was produced in relatively small quantities. It is regarded today as one of the greatest of the Chevrolet small-blocks, an engine that has been in production since 1955.

History
Chevrolet introduced the 350 cuin LT-1 in 1970, making it available in both the Corvette and Camaro. It was an optional engine in the Corvette, and available and as part of the high-performance ZR-1 option. Between 1970 and 1972, only 53 ZRs were produced, making it one of the rarest Corvettes. In the Camaro, the engine was available only through the high-performance Z/28 option, replacing the 302 cuin engine designed to compete in Trans Am racing's 305 cuin class installed in 1967-1969 cars.

The LT-1 had an 11.0:1 compression ratio, Holley 780 cuft/min 4-barrel carburetor, and solid lifters. For the first year the LT-1 was rated at 370 hp in the Corvette and 360 hp in the Camaro, both of these being brake horsepower (bhp) gross hp ratings. Despite the disparity in these horsepower ratings, there was no difference between the engines.

In 1971, the compression ratio was decreased to 9.0:1 and horsepower decreased to 330 hp, then the same in Corvette and Camaro. A net horsepower rating of 275 hp was also given. In 1972, the rating decreased again, then to a net of 255 hp. Gross horsepower was not given in 1972.

In 1970, a Nova could also be ordered with an LT-1 via a Central Office Production Order (COPO). Fifty of these were ordered by Don Yenko at Yenko Chevrolet and were converted into Yenko Deuces. Yenko also converted another 125 L65 Novas into LT-1 Deuces.

Production numbers

 * * 25 of these were ordered with RPO ZR1.
 * ** 8 of these were ordered with RPO ZR1.
 * *** 20 of these were ordered with RPO ZR1.
 * **** 50 of these were converted into Yenko Deuces.

1990s "LT1"
In 1992, General Motors introduced the LT1, a high-performance 350 cuin engine based on the Chevy small-block V8 and named as a tribute to the original LT-1. It was offered as a base engine on the C4 Corvette and a variety of other GM vehicles in several states of tune through 1997, including the Camaro Z/28, performance-package Pontiac Firebirds, police interceptors, a number of large luxury cars, and a luxury station wagon.

Its maximum performance ratings (as installed in 1996 Corvettes) were 300 hp and 340 lbft, well above the 275 net hp and 255 net hp ratings for the original LT-1 in 1971 and 1972, and the 300 ft lb (est) net torque for 1971 and 280 ft lb net for 1972, but well below the 1970 LT1 gross rating of 360 hp.