Preheat the oven to 400°.
In a small bowl mix together the garlic, parsley, rosemary, thyme, red wine vinegar, ½ cup olive oil, salt and pepper until completely combined. Set aside.
Next, cover the pork loins in 3 tablespoons of olive oil and season on all sides with salt and pepper.
Place the loins onto the rack in the roasting pan. Add about ¼ cup of the herb mixture over top of the pork loins and spread it around to cover the top.
Pour 3 cups of beef stock into the roasting pan and bake at 400° for 30 minutes.
Every 15-20 minutes baste the pork with the beef stock and pan drippings.
While the pork is cooking add the potatoes, carrots and brussel sprouts to a large bowl and toss with remaining 3 tablespoons of olive oil, salt and pepper until coated.
Evenly divide the vegetables around the pork loins in the roasting pan and cook for another 30-35 minutes or until the vegetables are tender and the pork is cooked through.
Serve everything with the extra chimichurri sauce.