Felix An easel and a poster board have been set up in the lobby of Felix Mexican Restaurant at Westheimer and Montrose. Polaroids of loyal customers and their families are tacked up on the board, and each is accompanied by a caption that tells how many years they have been coming to the restaurant, which opened in 1948. Quite a few Felix regulars have been eating there for 55 years. Some are fourth-generation fans. And while the price of the Mexican Dinner has gone up a bit from the 50 cents they charged in 1948, the flavors are the same. The chile con queso still tastes fabulous -- until it cools off and clots up. The awful spaghetti with chili gravy is still on the menu. And the combination plates, the enchiladas, and the chicken taco salad are just as wonderful as ever. So is the incredible 1940s Tex-Mex ambience.