Combine the roast and 2 cups of the salad dressing in a large plastic storage bag.

Squeeze out excess air, seal tightly, and massage to coat the meat all over.

Marinate in the refrigerator for at least 2 hours and up to overnight, turning the roast over at least once.

Preheat a heavy (preferably cast-iron) Dutch oven over high heat.

Add the oil.

Remove the roast from the marinade, and add it to the pan.

Brown on all sides, 4 to 5 minutes.

Sprinkle the meat with the seasoned salt and pepper.

Add the water and the remaining 1/4 cup salad dressing.

Cover, reduce the heat to low, and cook until very tender, about 3 hours, checking occasionally to see if additional water is needed.