TR5, TR250 and TR6 (inlet valve) ? TR2 to TR4A (inlet valve) and TR4 from engine no. CT21471 plus all TR4A (exhaust valve) ? Spitfire Mk3, Mk4 and 1500 (inlet valve and exhaust valve) ? GT6 (inlet valve and exhaust valve) ? 2000, 2.5PI and 2500 Saloon (inlet valve)