Pontiac engines have block code. This code will tell you the year it was to be used. However, these codes were used over from year to year. Together with the casting code and casting date you can determine where what the engine is. Starting in 1965 Pontiac began using a 2 digit letter code.
As a general rule, “W” coded blocks are manual transmission and “Y” coded blocks are automatics. And most of the “Z” coded blocks are also auto. The “X” coded blocks are a little of both.
Where to find the Engine Code:
The Engine codes will be found on the front of passengers side of the block, below the head. Above the 2 digit code will be the motor unit number, which is either 6 or 7 digits. It is not related to the VIN number.