Don’t listen to taco scholars who claim that the pork is too red, or that the flames are too hot, because workers at this tiny, much-loved East Harlem hole in the wall have managed the elusive balance of fat, salt, and char since 1990, when this place opened, and show no signs of slowing down. Wear comfortable shoes, since you’ll be standing at the counter opposite the busy cooks who are slicing and assembling all sorts of variously cooked meats (pig ears! pig stomach!) and tortillas, and be careful with the nine — nine! — salsas: The roja and habanero versions pack some serious heat. Unsurprisingly, tacos are the thing to get, with the al pastor carved to order from the spit and topped with sliced pineapple. The carnitas are pleasantly salty and crispy, and the barbacoa de chivo (goat) is warmly spicy and musky. For vegetarians, the flor de calabaza quesadilla is a nice option, with sautéed squash blossoms and Cotija cheese spilling out of a grilled corn (or flour) tortilla.