Engine Codes
Short answer: The clue is the partial VIN stamp (20P105982): the leading 0 means a 1970 car, and the P means it was built at the Pontiac assembly plant (which was building full-size cars like Catalina/Bonneville that year). For 1970, “YD” indicates a 2-barrel 400, ~290 gross hp from a full-size Pontiac — so this engine isn’t a 1967 Firebird 400.
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Content last modified: June 13, 2026 at 10:06 am
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i am having the same problem- I bought 1968 Firebird and was the told the engine was replaced. Found the marking for 350 but could not determine the Year. The code on front of engine block is
OC81981 YL
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