Looks great, just an FYI if you want it to be "correct". the 55331C like you have was actually the last version to use the standard intake and diaphragm carb, Like this one I redid for someone awhile back.
The early in the year revision to 56C was the introduction of the slanted intake, and the later 1971 revision 88C indicated the final small changes for the next couple of years of production till they went to the square shrouds and heavier flywheels ( about 1975 55388E). So if you are building more of them you could always swap those parts out at a later time :thumbsup:
you also want to salvage off your original carbs the choke lever ( I do the throttle lever as well) if you going to retrofit a new one on. They are a direct fit to those H50 carbs that BWM sells as replacements, but not to the HS replacment carbs......so the lever does not interfere with the exhaust.
Best of luck with your engines!