Not exactly a secret, Tacos al Carbon has been on Lake Worth Ave. a yellow, freestanding building just east of Military Trail in the western reaches of Lake Worth for what looks like some years now. There's a big, mostly working-class Mexican presence in the neighborhood, with a few Mexican (not pan-latin) grocery stores and restaurants within a few blocks.
It's a tiny place with woefully inadequate parking and a sign that says they're open 24/7, packed with small tables, self-serve coolers, and a walk-up window. The vacant lot next door houses a taco trailer (an annex for peak hours? same owners? beats me.)
Had a very tasty, meaty and moist tamale ($2) and tacos ($1.50 each) with lengua (tongue) and barbacoa (beef stew, not goat, alas). The meat fillings were great, tender and nicely spiced, the tortillas fresh and substantial, and the cilantro and vegetables applied liberally. In a move that'll upset some purists but delight everyone else, they put some tomato and shredded queso blanco on them, somehow without Americanizing the tastes and textures one bit, a trick I haven't seen before. Live with it. If chowhounds had been so doctrinaire about hot dogs a hundred or so years ago, we'd still be eating them with the bread on the side. These are not the archetypal taco (two flat corn tortillas, lots of meat, a little cilantro and onion, period, wrapped in waxed paper), but they're mighty good and unquestionably Mexican. I'd go out of my way to eat there again.
Don't bother with the horchata and the tamarind drink; both are from powdered mixes. And don't expect ameinities. This is a roadside joint if ever there was one.
Decent selection of Mexican junk food at the counter, and a (rather pricey, but not counterfeit) decent selection of Mexican music from corridos to rock en espanol.