Bring 6 quarts water to boil and add 2 tablespoons salt.
In a 12 inch to 14 inch saute pan, heat oil over medium high heat until just smoking. Add garlic, bell pepper and hot pepper and cook until soft, about 7 to 8 minutes. Add cockles and mussels and cook 1 minute, stirring regularly. Add white wine and bring to a boil. Meanwhile, drop pasta in boiling water and cook according to package instructions. Add butter to pan with mollusks and cook until clams and mussels are all open, about 3 minutes.
Drain pasta well and toss into pan with clams. Cook 30 seconds together, add parsley, toss well and serve in a warm serving bowl.