A gastric restrictor assembly is provided which includes a first longitudinal member, a second longitudinal member, a first connector and a second connector. The first and second connectors support the first and second longitudinal members in spaced relation. The second longitudinal member is rotatably supported between the first and second connectors and includes a bend or offset. The second longitudinal member is rotatable to rotate the offset in relation to the first longitudinal member to selectively vary the width of a channel defined between the first and second longitudinal members. In one embodiment, the second longitudinal member includes engagement structure for engaging a positioning tool and indexing structure for releasably securing the second longitudinal member at fixed positions of rotation in relation to the first longitudinal member.