9AT base caliber?

Hey, I am brand new to this forum and to Bulovas. I have been a hobbyist restorer of mainly Omegas, Longines and Zodiacs for a few years now and have just moved on to Bulovas. I recently purchased a terribly neglected Lone Eagle (or conqueror, you guys can decide once it's finished and posted.) As i disassembled and cleaned it i noticed a prominent FHF carved on the main plate. Does anyone know the base FHF caliber for this movement? Thanks!