second manifold insulator 160 and the crossover nozzle housing 170 the second end 114 can slide vertically as illustrated relative to the second manifold insulator 160 and the crossover nozzle housing 170 the leg manifold 110 has a melt passage 116 extending through it the melt passage 116 communicates at the first end 112 with a sprue passage 134 extending through the sprue housing 130 the melt passage 116 fluidly communicates at the second end 114 with a crossover nozzle passage 174 extending through the crossover nozzle housing 170 the leg manifold 110 is further supported along its length between a pair of central manifold insulators 180 one of which extends between the manifold plate 106 and the leg manifold 110 and the other of which extends between the leg manifold 110 and the injection plate 106 the manifold insulators 180 are received in respective recesses 182 and are provided with projections or locating spigots 184 which engage corresponding recesses 186 in the leg manifold 110 accordingly the central manifold insulators 180 constrain the leg manifold against the longitudinal movement vertical as illustrated in the region of the central manifold insulators 110 this has the effect of limiting longitudinal movement of the leg manifold 110 resulting from thermal expansion or contraction to the first and second ends 112 and 114 respectively in a preferred embodiment the central manifold insulators 180 may be located about midway along the leg manifold 110.