red was all early sierras (rs500 3 door, 2wd saph & early 4x4 saph,
green was late 4x4 saph with a cat and a lambda probe
blue was early escos( big turbo)
grey was last small turbo escos



ps, they are all the same as insofar as they will all fit, but the early ones had a boyonet type oil filler (quarter furn jobbie) and all the later ones had a screw in type which made a much better seal