In a large stock pot add water to a depth of 1 inch.
Bring to a boil and add clams and cover
Steam the clams for 6 to 8 eight minutes the clams will open
Remove meat from inside the clams and roughly chop it. Discard empty shells.
Reserve 1 1/2 cups of the clam juice
Chop and reserve the clams
Combine salt pork and 1/4 cup water in a heavy-bottomed stock pot or Dutch oven. over medium heat, stirring occasionally, until water has evaporated and pork has begun to brown and crisp in spots, about 8 minutes.
Add butter, onion, and celery.
Continue to cook, stirring occasionally, until onions are softened but not browned, about 4 minutes longer.
Add flour and stir to combine.
Add clam juice and stir to combine.
Add milk, potatoes, bay leaves, and a pinch of salt and pepper to the pot.
Bring to a boil, reduce to a bare simmer, and cook, stirring occasionally, until potatoes are tender and starting to break down, about 15 minutes.
Once potatoes are tender, pour the entire mixture through the fine mesh strainer into the bowl with the clam juice rapping the strainer with the back of a knife or a honing steel to get the liquids to pass through.
Transfer strained solids to the bowl with the chopped clams. You should end up with a white, semi-broken broth in the bowl underneath, and the chopped clams, potatoes, salt pork, and aromatics in the separate bowl.
Transfer liquid to a blender and blend on high speed until smooth and emulsified, about 2 minutes.
Return liquid and solids back to Dutch oven.
Add heavy cream and stir to combine. Reheat until simmering.
Season well with salt and pepper.