Bring a large pot of water to boil for pasta. In a large straight-sided skillet, heat 4 tablespoons olive oil over medium heat. Add sliced garlic and cook until sizzling, about 1 to 2 minutes. Add anchovies and stir until the anchovies break up and dissolve into the oil, about 2 minutes.
Add the clams to the skillet, along with the peperoncino and oregano. Ladle in about 2 cups pasta water. Bring to a simmer, cover, and cook until clams open, about 5 to 7 minutes. As the clams open, remove to a bowl. Meanwhile, add linguine to pasta water.
When all the clams are out, increase heat to high and add 1/2 cup of the parsley. Cook until liquid is reduced by half. Meanwhile, shuck the clams.
When the linguine is al dente and the sauce is reduced, add the pasta directly to the sauce. Cook and toss until the pasta is coated with the sauce. Add shucked clams and remaining ¼ cup chopped parsley, Cook a minute more, to blend the flavors, and serve.
Linguine with red clam sauce is almost never found in Italy, but a big seller in Italian American restaurants here in the United States. So, when you go to Italy, eat it as they do with white clam sauce, and never, ever ask for cheese to put on your linguine with clam sauce.