Preheat the oven to 375°F.
Heat the oil in a skillet, add the onions and cook until softened and translucent. Add the rice and cook for another minute.
In a large bowl, add the ground pork, salt, pepper, parsley, dill and the onion and rice mixture. Be careful with the salt, not too much is needed because the sour cabbage is already salty. Mix well using your clean hands.
Remove all the cabbage leaves and cut each leaf in half. Romanian cabbage rolls are traditionally smaller than the Polish cabbage rolls, so that's why I recommend cutting each leaf in half, otherwise you can use the entire leaf for one roll.
Fill each leaf with about a couple tbsp of the meat mixture and roll. Repeat with all the remaining meat and cabbage. If you have any cabbage left over, chop it up and spread it over the bottom of a big pot.
Put all the rolls in the pot, add the chopped bacon in between the cabbage rolls and add the tomato juice over the rolls. Add more water if needed, the juice should cover the cabbage rolls entirely. Cover the pot with aluminum foil or a lid.
Place in the oven and bake for 2 hours, remove the foil or lid and place back in the oven and cook for another 1 ½ to 2 hours. Serve hot with a bit of sour cream on top and with a side of polenta.