A flexible tack strip (30, 30′) is provided for mounting the rear hem (28) of a convertible top cover (22) to a vehicle body (12). The tack strip (30, 30′) is preferably glass-filled plastic material (30′) and is sufficiently flexible to enable deformation and insertion through the top storage compartment opening (16) when the topstack (18) is being installed on the vehicle body (12). The tack strip (30, 30′) has at least one stop member (38) which engages a stop clip (42) mounted on the body to limit the upward and forward movement of the tack strip (30, 30′) to secure the cover hem (28) and tension the cover (22) when the top is raised. An optional spring latch (46) can be included adjacent each stop clip to trap the tack strip when installed.