The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →There was no single “1979 Firebird engine.” Pontiac’s lineup used engines built by Buick, Chevrolet, Oldsmobile, and Pontiac, and which one a car could have depended on its trim and configuration. For an individual car, the quickest starting point is the fifth character of its VIN: the 1979 owner’s manual identifies that character as the engine code.
What engine came in a 1979 Pontiac Firebird?
It depends on the car. The owner’s manual lists seven VIN engine codes, spanning a Buick V6 and V8s from Chevrolet, Oldsmobile, and Pontiac. The table below reproduces the manual’s engine identification chart; it identifies the engine associated with a code, not a complete trim-by-trim ordering guide.
| VIN code | Engine listed in the manual | Carburetor | Division named in the manual |
|---|---|---|---|
| A | 3.8 L (231 cu. in.) V6 | 2-barrel | Buick Motor Division |
| G | 5.0 L (305 cu. in.) V8 | 2-barrel | Chevrolet Motor Division or GM of Canada |
| K | 6.6 L (403 cu. in.) V8 | 4-barrel | Oldsmobile Division |
| L | 5.7 L (350 cu. in.) V8 | 4-barrel | Chevrolet Motor Division or GM of Canada |
| W | 4.9 L (301 cu. in.) V8 | 4-barrel | Pontiac Motor Division |
| Y | 4.9 L (301 cu. in.) V8 | 2-barrel | Pontiac Motor Division |
| Z | 6.6 L (400 cu. in.) V8 | 4-barrel | Pontiac Motor Division |
The table keeps distinctions that are easy to blur: a 301 could be a two-barrel or four-barrel version, and the 403 and 400 were different engines from different GM divisions despite both being listed as 6.6-liter V8s. The chart comes from page 90 of the 1979 Pontiac Firebird Owner’s Manual, whose scan is hosted by ManualsLib. The manual says its specifications are informational and points readers to other cautions and instructions in the book.
What engines were available in a 1979 Trans Am?
Historical summaries describe the Trans Am with several distinct engine configurations, not one universal engine. Hagerty’s account lists the Pontiac 301 L37, Oldsmobile 403, and Pontiac 400 L78 or W72 configurations. These are Hagerty’s published descriptions, not a complete factory ordering chart. For an individual car or a restoration decision, confirm the VIN code and consult documentation specific to the car and its market.
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The 301 appears in two carburetor configurations in the owner’s manual: Y for the two-barrel and W for the four-barrel. Hagerty describes a 2-barrel 301 rated at 135 bhp and a 4-barrel 301 rated at 150 bhp. Treat those as Hagerty’s historical-summary figures for the described configurations, not as a single rating for every 301 application.
Oldsmobile 403
The manual identifies the 403 as an Oldsmobile 6.6-liter, four-barrel V8 under VIN code K. Hagerty describes a Trans Am 403 configuration rated at 185 bhp. That figure should remain attached to Hagerty’s described application rather than generalized to every 403-equipped Firebird.
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Pontiac 400
The 400 is the Pontiac-built 6.6-liter, four-barrel V8 identified by code Z. Hagerty names L78 and W72 configurations among its Trans Am offerings. The sources cited here do not establish a fully reconciled power figure for every 400, transmission, and trim combination.
How did engine availability differ by Firebird trim?
Trim matters: a menu described for the broader Firebird range should not be assumed to apply to every Trans Am, or vice versa. Hagerty describes a 2-barrel 301 rated at 135 bhp as an option on the base Firebird, Esprit, and Formula, and a 4-barrel 301 rated at 150 bhp. Its account also describes Chevrolet-built 305 and 350 options for those trims, while listing Pontiac 301, Oldsmobile 403, and Pontiac 400 L78 or W72 configurations for Trans Am.
Tran-Zam’s specialist reference adds that the base Firebird and Esprit continued with the Buick 231 V6 as standard equipment and could be had with either 2-barrel or 4-barrel 301s; it also notes the Chevrolet 350 for high-altitude areas. These secondary summaries provide useful trim context, but they are not a substitute for a factory ordering guide when a precise availability question depends on trim, transmission, market, or other configuration details. The owner’s manual’s VIN chart is an engine-identification aid, not a full availability matrix.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How do I tell if my 1979 Firebird has a 301, 400, or 403?
Start with the fifth character of the VIN. Pontiac’s 1979 owner’s manual states, “The fifth character of your VIN is the Engine Code.” Its chart maps Y and W to the two 301 versions, Z to the Pontiac 400, and K to the Oldsmobile 403.
- Locate the car’s VIN and read its fifth character.
- Compare that character with the owner’s-manual chart: Y or W indicates a 301, Z a 400, and K a 403.
- If you are authenticating a car or selecting restoration parts, verify the engine and configuration with appropriate service documentation and inspection. The VIN chart identifies the engine code; it is not a complete guide to block stamps or proof that the engine currently installed is original to the car.
For a 301, the code also distinguishes carburetor configuration: Y is the two-barrel and W the four-barrel. A VIN code is a practical first check, but it does not by itself settle every question about a car’s present engine, replacement history, or authenticity.
Why do horsepower figures for 1979 Firebirds differ?
A displacement alone is not enough to determine a power rating. Carburetor, engine configuration, trim, transmission, market, and the rating source can all matter. The cited historical summaries do not reconcile every horsepower and torque figure across those combinations, so a single exhaustive ratings table would overstate what they establish.
When quoting a number, name the specific engine configuration and attribute the figure. For example, Hagerty gives 135 bhp for the two-barrel 301, 150 bhp for the four-barrel 301, and 185 bhp for its Trans Am Oldsmobile 403 description. Those are selected summary values, not a complete set of factory ratings for every 1979 Firebird. A factory specification or ordering document is the better reference when a definitive rating for a particular engine and transmission is required.
How many 1979 Firebirds were sold?
Hagerty reports 211,453 Firebirds sold for the 1979 model year in its historical valuation account. That is a total model-year sales figure; it does not tell how many cars had any particular engine.
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