A ball valve assembly includes an enclosure for supporting the ball valve during actuation. In one embodiment, the enclosure can be a split enclosure, and can have trunnion support apertures for engaging trunnions on the ball valve. In one embodiment, a pair of link arms are used to transfer force from a pair of actuation members to the ball valve. The link arms can be located in a recess on the actuation members, such the actuation members and the face of the trunnions define a cavity to enclose and protect the link arms.