[Gaz64]

Not sure on the DCOs but on DCOEs, IDF, IDAs etc, the suffix can point to number of, and placement of transfer holes.

Some carbs have only two holes, some carbs have 3,4 or 5 holes transition holes.

I don't know of any other differences, taking other replaceable variables into account.

I would pull one of each of the carbs off, and observe the transition hole number and placement in relation to the butterfly at say 1/4 turn open.