What year did Pontiac put the biggest engine in there Montana van?

Pontiac offered the largest engine option for the Montana van in 2005, when it introduced a 3.9-liter V6 engine. This engine provided enhanced performance compared to previous models, catering to customers looking for more power in their minivan. The 3.9-liter engine was part of Pontiac's effort to update the Montana lineup during its later years.