was the only Corvette engine for 1981. It produced and of torque from 8.2:1 compression, exactly the same as the 1980 L48, but added hotter cam and computer control spark advance, replacing the vacuum advance. The L81 was the first Corvette engine to employ a "smart carburetor." The 1980 Rochester Quadrajet was modified to allow electronic mixture control, and an ECM (Engine Control Module) supplied with data from an exhaust oxygen sensor, modified the fuel-air mixture being fed to the engine. LS9 Years: 1969-1986 The LS9 was GM's 350 cubic inch truck engine used in C/K/G 10/20 models under GVWR (gross vehicle weight rating). The LS9 used a Rochester 4 bbl carburetor, and its power ratings for 1984 were at 3800 rpm, and torque at 1600 rpm. A version using a closed-loop carburetor was used with the California emissions package in its final years. The LS9 and LT9 engines were replaced for 1987 by the L05 TBI (throttle-body fuel injection) engines. Most of the small block engines in this timeframe were built at either the Flint engine plant in south Flint, Michigan or at St. Catharines, Ontario. The Flint plant was producing about 5,200 engines per day in the mid-1980s, and had a slower, separate line for the TPI engines used in the Camaro and Corvette. (Source: 1984 Chevrolet Truck Data Book.) LT-9 Years: 1981-1986 The LT-9 served as GM's truck-based heavy emissions variant of the supplied in K20/K30 pickups, G model passenger and cargo vans (built in Lordstown, OH and later in Flint, MI) and with the P30 chassis used for motorhomes and stepvans. The LT-9's listed specifications are at 3,800 rpm and of torque at 2,800 rpm with 8.3:1 compression. LT-9's were carbureted with Rochester Quadrajets from factory and are generally 4-bolt mains. The LT-9 is often known by VIN code as the "M-code 350." The LT9 was used in models with GVWRs (gross vehicle weight ratings) over . L83 Years: 1982, 1984 The 1982 L83 was again the only Corvette engine, producing and of torque from 9.0:1 compression. Since GM did not assign a 1983 model year to production Corvettes, there was no L83 for 1983. This was also the only engine on the 1984 Corvette, at and of torque. The L83 added "Cross-Fire" fuel injection (twin throttle-body fuel injection). L98 Years: 1985–1992 The new 1985 L98 350 added tuned-port fuel injection "TPI", which was standard on