Preheat oven to 350 degrees. Place the unwrapped garlic cloves into a small ramekin and drizzle with 2 tablespoons of olive oil. Cover the dish with foil and bake for about 15-20 minutes or until the garlic is tender. Remove the pulp from the peel and place in a small mixing bowl. (See note)
Add the parsley, cilantro, vinegar, honey, oregano, red pepper and 1/3 cup of olive oil. Stir all ingredients together and season with salt and pepper. Set aside.
Preheat a gas grill on high with the lid closed.
Once preheated, turn off half the burners and put the roast on the indirect heat side of the grill. Cover and grill, turning once, until an instant-read thermometer inserted in the thickest part of the meat reads about 100 degrees (about 30 minutes.) Move the roast to the direct heat and grill until lightly charred and the thermometer reads 115-120 degrees (about 5 minutes.)
Remove the roast from the grill and allow it to rest for 15 minutes before slicing. The internal temperature will continue to rise off the heat.
Slice the roast against the grain and serve with the chimichurri. The thinner parts of the roast may be closer to well done depending on your cut of meat.