Masa Harina and Cornmeal, are not the same...
Cornmeal tastes like corn, like cornbread or Polenta.
Masa Harina is finely ground Hominy. Hominy, though from corn, is totally different.
wiki here: Masa - Wikipedia, the free encyclopedia
Hominy is white, has little flavor. When ground, it's more like white baking flour.
My Gosh. Here, Masa Harina is so normal. You can buy sacks at most Gas Stations!
I think you Must source some for Tamales, or they won't be right.
Try the Ethnic Section of your grocer, or try to find Hispanic Market near you. That section will have all the Tamale spices you need also..
Eric, Austin, Tx.