Randy Stocker said:The ?F? motors (F,FE,F2, FS) are larger in both bore spacing and deck height than the ?B?s are are mostly unrelated. Little to nothing will interchanges between the 'B' and 'F' motors, even the bellhousing bolt pattern is different from the 'B' motors.
The 'F' engines are the 'big blocks' of the 4 cylinders. They are long stroke motors and are generally not designed for high revs. All were cast iron SOHC with the exception of the FS and FE3.