An ink manifold for supplying liquid ink to a heater chip of an inkjet printhead. Ink ports on one side of the manifold feed liquid ink to the ink channels on the other side of the manifold, and thus to the backside ink trenches of the heater chip. The placement and number of ink ports formed in the ink manifold are optimized so that when the heater chip and the ink manifold are scaled down in size, the ink carrying capacity of the printhead components is not compromised. Similarly, when the ink manifold is scaled down, the optimization process allows the seal width between the ink port features of the manifold to be maintained above a specified minimum.