A valve housing blank comprises a receiving space for a valve insert having a longitudinal axis. At least two first pairs of supply ducts, which are opposite to each other with respect to the longitudinal axis, extend laterally from an outer side of the blank towards the receiving space. The pairs of supply ducts, as seen in the direction of the longitudinal axis, are arranged so as to be offset relative to each other. Only one of the supply ducts is open towards the receiving space. The other supply ducts are closed off from the receiving space by a destroyable dividing wall.