An assembly (300, 700, 1400) comprising: an actuator; a turbine housing (310, 710, 1410) that comprises a bore (312, 712, 1412), a conical wastegate seat (326, 726, 1426) and a wastegate passage (325, 725) that extends to the wastegate seat (326, 726, 1426); a bushing (342, 742, 1442) configured for receipt by the bore (312, 712, 1412); a control linkage (340, 1440) that comprises a control arm (344, 1444) operatively coupled to the actuator; a rotatable wastegate shaft (352, 752, 1452) configured for receipt by the bushing (342, 742, 1442) and operatively coupled to the control arm (344, 1444); a wastegate arm (354, 754, 1454) that extends from the wastegate shaft (352, 752, 1452); and a wastegate plug (356, 756, 1456) that is a flapper valve that extends from the wastegate arm (354, 754, 1454), characterised in that, the wastegate plug (356, 756, 1456) comprises a toroidal contact portion that contacts the conical wastegate seat (326, 726, 1426) to cover the wastegate passage (325, 725) in a closed state and a substantially hemispherical shell portion (357, 757) that extends into the wastegate passage (325, 725) in the closed state and wherein the toroidal contact portion and the substantially hemispherical shell portion (357, 757) define clearances with respect to the conical wastegate seat (326, 726, 1426) in an open state, and in that, the toroidal contact portion and the substantially hemispherical shell portion (357, 757) of the wastegate plug (356, 756, 1456) being configured to reduce impact of pressure on the actuator as the actuator rotates the wastegate plug (356, 756, 1456) with respect to the wastegate passage (325, 725) over a range of angles to about 30 degrees open. an actuator; a turbine housing (310, 710, 1410) that comprises a bore (312, 712, 1412), a conical wastegate seat (326, 726, 1426) and a wastegate passage (325, 725) that extends to the wastegate seat (326, 726, 1426); a bushing (342, 742, 1442) configured for receipt by the bore (312, 712, 1412); a control linkage (340, 1440) that comprises a control arm (344, 1444) operatively coupled to the actuator; a rotatable wastegate shaft (352, 752, 1452) configured for receipt by the bushing (342, 742, 1442) and operatively coupled to the control arm (344, 1444); a wastegate arm (354, 754, 1454) that extends from the wastegate shaft (352, 752, 1452); and a wastegate plug (356, 756, 1456) that is a flapper valve that extends from the wastegate arm (354, 754, 1454), characterised in that, the wastegate plug (356, 756, 1456) comprises a toroidal contact portion that contacts the conical wastegate seat (326, 726, 1426) to cover the wastegate passage (325, 725) in a closed state and a substantially hemispherical shell portion (357, 757) that extends into the wastegate passage (325, 725) in the closed state and wherein the toroidal contact portion and the substantially hemispherical shell portion (357, 757) define clearances with respect to the conical wastegate seat (326, 726, 1426) in an open state, and in that, the toroidal contact portion and the substantially hemispherical shell portion (357, 757) of the wastegate plug (356, 756, 1456) being configured to reduce impact of pressure on the actuator as the actuator rotates the wastegate plug (356, 756, 1456) with respect to the wastegate passage (325, 725) over a range of angles to about 30 degrees open.