29G = 3.9 Liter, 9.35 compression, Defender to 1996
30G = 4.0 Liter, 9.35 compression, Defender, 1997-on
31D = 3.5 Liter, 8.13 comp., RR 1987 & 1988
35D = 3.9 Liter, 9.35 comp., manual trans., Discovery
36D = 3.9 Liter, 9.35 comp., A/T, RR 93-95, DS
38D = 3.9 Liter, 8.12 compression, 87-92 Range Rover
40D = 4.2 Liter, 8.94 compression, 93-95 Range Rover
42D = 4.0 Liter, high compression, New Range Rover
46D = 4.6 Liter, high compression, New Range Rover
50D = 4.0 with 9.35 compression, Discovery
Note: Engine numbers are located on the engine block next to the dipstick hole.