Buick LT1's Specificationsby Kay Layne
The LT1 was a small-block engine manufactured by General Motors. It replaced the L98 engine, and produced better mileage and torque and had 20 percent more horsepower. The LT1 was first placed in the 1992 Corvette. In 1994, the engine was placed in the Buick Roadmaster. The LT1 was manufactured until 1997, when it was replaced by the LS1.
The Buick's LT1 motor was slightly different from the LT1 placed in the Corvette. The Buick 5.7-liter engine came with two-bolt mains and cast-iron heads, while the Corvette's had four-bolt mains and aluminum heads. The Buick LT1 produced 265 horsepower, 40 horses less than the Corvette's engine, but weighed much less.
The LT1 uses a reverse-flow engine-cooling system. This means that coolant flows from the heads down through the block. This keeps the heads cooler and allows higher and more consistent cylinder temperatures. The LT1 does not need a special radiator, but it does need an overflow tank to make sure that there is no air in the system.
In 1994, a sequential port injection was added. The following year, the distributor was enlarged and received a drain tube to remove excess moisture. Then, in 1996, the LT1 received a second catalytic converter and an extra 10 horsepower.
General Motors also manufactured a 4.3-liter engine called the L99, which is a virtual lookalike of the LT1. The easiest way to differentiate between the two engines is to check on the block. Look in front of the bellhousing mount. It will be marked with either 5.7L or 4.3L.