In small bowl, mix garlic powder, salt, pepper and parsley; rub well
into meat. Let stand 30 minutes at room temperature.
Meanwhile, soak 2 cups red oak chips in water for at least 20
minutes (optional). Prepare a medium-size fire on one side of a
charcoal or gas grill. Add chips to fire, if using. Set tri-tip over fire,
fat side up (with a gas grill, close lid), and brown well, 3 to 5
minutes; turn over and brown other side.
Move meat over area of the grill without fire, cover, and turn every
10 minutes or so, until an instant-read thermometer inserted into
thickest part registers 125 to 130 degrees, 25 to 35 minutes.
Place meat on cutting board to rest at least 15 minutes. Slice
across the grain.