| LT-1 | |
| Manufacturer: | General Motors |
| Production: | 1970–1972 |
| Configuration: | Naturally aspirated 90° V8 |
| Head: | Cast iron |
| Valvetrain: | OHV 2 valves × cyl. |
| Fueltype: | Gasoline |
| Fuelsystem: | Carburetor |
| Coolingsystem: | Water-cooled |
| Compression: | 9.0:1, 11.0:1 |
| Displacement: | 3501NaN1 |
| Bore: | 4inches |
| Stroke: | 3.48inches |
| Block: | Cast iron |
| Power: | NaNhp (gross) |
| Torque: | NaNlbft (gross) |
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.
Chevrolet introduced the 3501NaN1 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 3021NaN1 engine designed to compete in Trans Am racing's 3051NaN1 class installed in 1967-1969 cars.
The LT-1 had an 11.0:1 compression ratio, Holley 780cuft/min 4-barrel carburetor, and solid lifters. For the first year the LT-1 was rated at 370hp in the Corvette and 360hp 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 330hp, then the same in Corvette and Camaro. A net horsepower rating of 275hp was also given. In 1972, the rating decreased again, then to a net of 255hp. 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.
| Camaro | Corvette | Nova (COPO) | ||
| 1970 | 8,733 | 1,287* | 52**** | |
| 1971 | 4,862 | 1,949** | ||
| 1972 | 2,575 | 1,741*** |
In 1992, General Motors introduced the LT1, a high-performance 3501NaN1 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 300hp and 340lbft, 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.