TR4A IRS fitted with overdrive unit 22/61753 ? TR5 and TR250 (1967-68) ? TR6 to September 1972 (P.I. models tochassis no. CP77718, carburettor models to chassis no. CC85737)
TR2 to TR4A (1953-67) ? TR5, TR250 and TR6 with 'A' Type overdrive (to September 1972) ? Spifire Mk3 and early Mk4 with 'D' type overdrive to chassis no. FH60000 andFM10000 (January 1967 to August 1973) ? GT6 with 'D' type overdrive (1966-73)