Place the pork tenderloin on the grill over direct heat at 400 degrees.
Turn and rotate the pork every 2-3 minutes to get a nice crust and sear on the outside.
Remove the pork from the grill when it hits 145 degrees internal temperature and cover with foil.
While the pork is resting, combine all the chimichurri ingredients. Start off with finely chopping an entire batch of parsley and cilantro. Next add a tablespoon of freshly minced garlic, crushed red pepper flakes, salt, red wine vinegar, freshly squeezed lemon juice and olive oil. Mix these ingredients together with a spoon, not a food processor