The 1980s saw General Motors develop several improvements to the 305 introduced the decade before.
This includes initial attempts at fuel injection and GM’s “CCC” (computer command center” engine management.
The 305 remained a popular engine at GM, featuring in almost every production vehicle in some form throughout the 1980s.
First introduced in 1976, the LG3 remained in production until 1982, ultimately being phased out in favor of the LG4 and more efficient and performance-minded engine configurations.
The LG4 was introduced in 1978 using a very similar configuration to the LG3. Changes to the fuel management system gave it approximately 15-30 more horsepower, however. Various iterations of the LG4 remained in production until 1987.
In production from 1982-84, the LU5, also known as the Crossfire EFI 5.0, including a dual TBI injection system designed from the 1969 Chevy Camaro Z28’s Crossfire Intake. This system was placed on top of the stock LG4 305, but failed to produce the kind of performance upgrade GM thought it would.
These engines are uncommon because, as an early TBI, most owners, mechanics, and dealerships lacked the capabilities to work on them efficiently.
The L69 began production in late 1983. It was GM’s high-performance 305, available in the Firebird Trans Am, Camaro Z28, IROC-Z, and the Monte Carlo SS. It is one of the best-performing engines in its run, though a lot of that can be attributed to the aggressive camshaft, four-barrel carburetor, and the F-Body’s free-flowing exhaust system.
The LE9 included a four-barrel carburetor and the LM1 cam. It ran from 1981 to 1986. It was the high-output model used predominantly in GM heavy-duty trucks and large vans.