Help with engine identification

[conan.wade.9]

Hi I need help in identifying the engine in my 77 firebird. I have located two codes. one looks like GM-3 and the other P157. Any help is appreciated

 

[92 Sunbird LE]

P is a B? ( Feb ? 15th 1977 the heads were cast) P157 is the date code

Head code is in the middle of the head between the spark plugs.

http://www.antiquecarparts.net/tech04.htm


Engine code look up here ;http://www.teufert.net/identify/identify.htm

Doug in P.R.

 

[92 Sunbird LE]

The "GM-3" is the foundary stamp to identify the foundary the head was cast at.

Doug in P.R.