Heres the deal..I'm ready to buy a 1962 394 Oldsmobile engine ( sitting in a garage on jack stands out of the car ) but I'm having a tough time decoding this one.. Stamped on the driver side cylinder head is GXXXXXXO.. G means 1962 the X's are the useless production number and what does the letter O stand for? I cant find it anywhere in manuals or other sources. Its weird cause it has the chromed valve covers, chromed air cleaner, chromed down draft tube and chromed oil fill cap. Got the 4bbl with a generator on it. The decal on the air filter is long gone and the person who is selling it has no idea where it came from ( deceased father had it ) Is this a Starfire block or some other optioned block I never heard of? Thanks for your help

 

The only 394s that displayed the prefix letter G were built for the 61 & 62 model years. The suffix letters used in those years decode as follows: S-Starfire, E-Export, L-Low Compression. There is no letter O specified in the literature.

However, it's quite possible that this engine is a 1961, and the 7th digit was in fact a number used to identify one of three horsepower ratings (i.e. 0-275hp, 1-325hp, 2-330hp). See image attached.

In any case, it's most likely a SkyRocket or Starfire engine, as identified by the G-code. The standard 394s for 1962 were coded with the letter F as the prefix.