Bob's Red Mill makes grits. I recently saw a bag at Fou d'Ici on Maisonneuve but you can probably find some most places where Red Mill products are sold.
Grits is coarsed-ground cornmeal, nothing else. As long as you don't use fine or medium grind, you should end up with the expected result.
I thought grits (hominy grits) were nixtamilized http://en.wikipedia.org/wiki/Nixtamal... which improves nutriment availability.
In Québec, corn treated this way is called maïs lessivé. Indigenous people up here made a dish called sagamité with it, game and other available ingredients.
Though perhaps not all grits undergo this process. Indeed the Bob's Red Mill kind just seems to be ground corn.