Abstract: An extrusion head (1) defined by a number of superimposed plates (7,8,9,10) and by a casing (55) housing the plates (7,8,9,10) and defining two shoulder surfaces (68,69) forming an angle and perpendicular to the plates (7,8,9.10); the plates (7,8,9,10), when packed together, defining an intermediate guide duct (35) for guiding reinforcing wires and two supply ducts (11,23) for supplying extruded elastomeric material located on opposite sides of the intermediate duct (35), and providing for locking together a wire guiding device (36) and a die (37) presenting respective flat shoulders (42,43;50,51) parallel to a first (68) of the shoulder surfaces (68,69) and pressed by the plates (7,8,9,10) into contact with one another and with the first shoulder surface (68), with the die (37) located between the first shoulder surface (68) and the wire guiding device (36).