Second Generation GM small block V8

This article is a stub.

LT1

In 1992, GM created a new-generation small-block engine called the LT1, recalling the 1970 LT-1 moniker. It displaced 5.7 liters and was a 2-valve pushrod design. The LT1 used a reverse-flow cooling system which cooled the cylinder heads first, maintaining lower cylinder temperatures and allowing the engine to run at a higher compression than its immediate predecessors.

This engine was used in:

1992-1996 Chevrolet Corvette C4 1993-1997 Chevrolet Camaro Z28 1993-1997 Pontiac Firebird Formula and Trans Am 1994-1996 Buick Roadmaster 1994-1996 Cadillac Fleetwood 1994-1996 Chevrolet Caprice 1994-1996 Chevrolet Caprice Police Package 1994-1996 Chevrolet Impala SS 1994-1996 Chevrolet Caprice Wagon 1994-1996 Buick Roadmaster Wagon

There were a few different versions of the LT1. All feature a cast iron block, with aluminum heads in the Y and F bodies, and cast iron heads in the B and D bodies. Corvette blocks had four-bolt mains, while most other blocks were two-bolt mains.

The 92-93 LT1s used speed density fuel management, batch-fire fuel injection and a dedicated engine control module (ECM). In 94 the LT1 switched to a mass airflow sensor and sequential port injection. A new, more capable computer controlled the transmission as well as the engine and got a new name: powertrain control module (PCM). Where the ECM held its calibration information in a replaceable "chip", the PCM was reprogrammable through the diagnostic port.

The early Opti-spark distributor had durability problems and a revised version was introduced on the 1994 B-Bodies and in 1995 on the Y and F-Bodies. 1996 saw major revisions for OBD-II - a second catalytic converter on the F-body cars (which was standard since 1995 in California), rear oxygen sensors to monitor catalyst efficiency and a crank position sensor for misfire detection. Some OBD-II features had been added to the Corvette starting in 1994 for testing purposes. The 1997 model year Camaro and Firebird were the last year for this engine in a GM production car.

The 1992 LT1 in the Y-body was factory rated at 300 hp (220 kW) and 330 lb·ft (447 N·m). 96 LT1 Y-bodies were rated at 300 hp (220 kW) and 340 lb·ft (461 N·m). The 93-95 F-bodies were rated at 275 hp (202 kW) and 325 ft·lbf (439 Nm), while the 96-97 cars were rated at 285 hp (210 kW) and 335 ft·lbf (452 Nm). The 96-97 WS6 F-bodies were rated at 305 hp (227 kW). The 94-96 B and D-body version was rated at 260 hp (191 kW) and 330 ft·lbf (446 Nm).

LT5

The LT5 engine was a DOHC 5.7L V8 designed by Lotus. It is not technically a member of this engine family, but it is included here because it was current at the same time and because its RPO designation leads many people to believe that it is related.