If you're new to the Pontiac hobby, you may not know exactly where to find the two-letter block code, which designates your engine's original application.
It's usually stamped on the face of the block to the left of the water pump.
It's much easier to see when the engine block is cleaned, as shown here.
So Pontiac sleuths, what kind of car did the Pontiac code-XF block in the photo originally come in?
Special thanks to engine builder John Lombardi for providing this photo.