Ok, here is a real downeast clam chowder.

Scrub live clams. Put them into a pot in about a pint of water and cook until they open. (As Barry said, discard any that don't open). Shuck the clams, chop if desired, but downeasters prefer them whole.
Let the broth stand so the particles will settle.Pour off the juice. Add enough water to make two quarts.Fry 3 or 4 slices of salt pork until crisp. Chop them and add to the broth. Chop 3 onions, 3 or 4 medium potatoes add to the broth. Simmer about 1/2 hour. Add clams. Add one can of evaporated milk, (UN sweetened)and a chunk of butter.
Tomatoes may be added if you want to spoil the whole thing. If you don't like evaporated milk, use whole milk.