1. Preheat grill to high. Stack 2 2-foot-long pieces of heavy-duty foil on top of each other. Arrange half of clams in center of foil. Drizzle with 1 Tbsp. olive oil and 1/4 cup wine. Sprinkle with half of garlic and half of parsley. Fold up foil to seal, leaving room for clams to open up. Repeat with 2 more pieces of foil and remaining clams, oil, wine, garlic and parsley.
2. Grill foil packets with grill covered until clams open, 10 to 12 minutes. Open packets carefully. Transfer contents to 4 shallow bowls and serve immediately with crusty bread, if desired.