Boil the pork, drain and cut into strips. Bring the pork broth to a boil and add in the shrimp shells and head. Remove the shells and head from the broth and reserve the liquid for late use.
In a large wok, heat oil and saute onion and garlic until aromatic. Add in pork and shrimp and saute for 3 minutes.
Pour the soy sauce, patis and black pepper and saute for another 3 minutes. Pour 8 cups of pork and shrimp broth. Bring to a boil and simmer for another 5 minutes.
Add in the noodles and cover. Simmer for about 5 to 8 minutes or until the dried noodles have absorbed most of the broth. You can add more water if it too dry.
Next is add in the vegetables and cook for another 3 minutes or until the vegetables are cooked. Stir until all the ingredients are well mixed. Season with liquid seasoning according to our desired amount and taste.
Transfer to a serving dish and serve with calamansi and patis as condiment.