[jp_waltz]

im pretty sure most companies make a 27F battery. The 27F is just the size and configuration of the battery and the orientation of the terminals. Like Thundra said, we need an F so the terminals are in the correct location for the cables. I have a napa battery and im very happy with it. You might want to search here a bit, there is a lot of info and opinions regarding this subject.
Good Luck,
Paul