@ST: agree about the carbs (they are indeed Bing, type 54 I think) and they have a membrane operated sleeve regulating the airflow over the nozzles, so yes they are "constant something". The goal is to avoid the need for a mixture control.
And agree again, the fuel pump uses the simple diaphragm technology, one reason for this is that it will only pump as much fuel as the carbs will take up.
Lastly: I recently replaced the Pierburg fuel pump (it was seriously damaged and the repair was only so so) with the newer Italian one (is that the one called "Corona"?). The new pump does have an overflow exit tube so it must have some kind of over-pressure relief indeed.