Thoroughly rinse your potatoes in cold water, and dry before peeling. Cube the potatoes into 1/2-inch cubes. Finely dice a medium onion. Wash and dry the celery, trim and quarter lengthwise, then slice into 1/4-inch pieces. Dice slices of uncooked bacon. Set aside.
Open the cans of chopped clams, and reserve the juices in a measuring cup. Place the chopped clams in a medium bowl. Set both separated clam juice and clams aside.
In a large pot over medium-high heat, melt the butter. Add the onion and celery - sauté until soft and translucent. Stir in the diced bacon, and the flour.
Carefully add the cubed potatoes to the large pot. Pour in the stock, reserved clam juice from the measuring cup, bottled clam juice, half-and-half, and heavy cream. Stir until well combined.
Bring to a simmer, stirring frequently. Once the chowder starts to thicken, reduce the heat to medium-low. Continue to cook uncovered for 20 minutes or until the potatoes are fork tender and chowder is heated through.
Add the chopped clams, cook for additional 2-3 minutes or until the clams are firm. Season the chowder with salt and pepper to taste. Sprinkle with fresh chopped parsley. Serve immediately. Enjoy!