Cut bacon, onion, celery, and potato into cubes. Set them aside.
Heat a large pot over medium heat, add bacon, and cook.
Add onion, and celery, potato, garlic, and saute until softened. Add salt and pepper.
Sprinkle flour into the vegetable, and coat them with flour.
Add chicken stock, and bring to simmer.
Add half and half.
Add clams and bring to simmer, stirring consistently. Reduce the heat to medium-low and cook, often stirring for about 20 minutes.
Serve hot with parsley.