One or more nozzles define separate nozzle channels. The nozzles are coupled to a manifold, so that each of the nozzle channels communicates with a different mold gate. A molding material distribution insert is coupled to the manifold and has a body defining a distribution channel and a plurality of drop channels equal in number to the nozzle channels. The distribution channel is an open distribution channel formed on an outer surface of the body and enclosed by the manifold. The drop channels intersect the distribution channel and exit the body at a different one of the nozzle channels. A valve pin bushing can extend into the drop channels. Valve pins can extend from actuators, through the valve pin bushing and the drop channels, and to the mold gates. A valve pin holder can be coupled to the actuator and coupled to heads of the valve pins.