It displaced , and was a 2-valve pushrod design. The LT1 used a reverse-flow cooling system which cooled the cylinder heads first, maintaining lower combustion chamber temperatures and allowing the engine to run at a higher compression than its immediate predecessors. This engine was used in: Y-body: 1992–1996 Chevrolet Corvette C4 F-body: 1993–1997 Chevrolet Camaro Z28, B4C and SS 1993–1997 Pontiac Firebird Formula, Trans Am, and Firehawk B-body: 1994-1996 Buick Roadmaster 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 D-body: 1994–1996 Cadillac Fleetwood 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 main caps, while most other blocks were two-bolt main caps. Block castings remained the same between 2 and 4 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 PROM chip, the 94-95 OBD1 PCMs are reprogrammable through the diagnostic port. The early Optispark distributor had durability problems, and a revised version was introduced on the 1994 B-Bodies and on the 1995 Y and F-Bodies. Changes include a vacuum port to draw filtered air through the distributor to remove moisture and ozone and a revised drive system which uses an extended dowel pin on the camshaft rather than a separate splined shaft in the camshaft gear. 1996 saw major revisions for OBD-II: a second catalytic converter on the F-body cars, rear oxygen sensors to monitor catalyst efficiency, and a new engine front cover with a crankshaft position sensor. 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 before it was replaced by the LS1, which was already in the Corvette for 1997. 1992 LT1s in Corvettes were factory rated at and . 1996 LT1 Corvettes were rated at and . The 93–95 F-bodies were rated at