Thanks to previous posts by Steve Drucker, I tried this place Friday eve. The Taco de Lengua (tongue) is without question the best single thing I've eaten so far in the entire Clayton - Franklin (NC) area. Rich and spicy and just good. The other tacos I tried (Al pastor and chorizo) were also really good, as were the tamales which were outstanding. This place, which is really a grocery store not a restaurant, must be on the to do list of any serious chowhound within 100 miles. They have several other things on the "menu" (which is a few photocopies taped to the wall), and everything I saw on other tables also looked good. Warning--if you ever should go, this is a true hole-in-the-wall so don't expect ambiance.
It's right behind the Chevy dealer, in a row with several Mexican places.