What do the colors represent on the DD’s injectors?

[Barn Owl]

What do the colors represent on the DD's injectors? I often hear people give a color with their injector size. For example: Brown tag N65. How many colors are there and what do they represent? It looks like I have Black N70. There is not a tag, but the background the size is stamped on looks black.

[Barn Owl]

Add to that: What does the N stand for and are there different letters?

[TomC]

There are so many injectors available, I don't know if that can be answered.  N injectors indicated a higher performance injector that could be used with 4 valve heads.  Brown were for transit buses, blue were for California clean tip.  The last injectors were either 7G65 (7 hole tip for 71 series) or 9G75 (9 hole tip for 92 series-which I have on my 71 series-no smoke).  My first 92 series had 9A90's. Now they are 9G90's.  The best is to get the book on them-which I don't know where you'd find that now.  Good Luck, TomC