Read this article on a shop's development of an early Monaro. This car has significant differences to GTOs - 305hp, higher gearing and different trans.
Of interest in part 2 is the trials to produce cold air systems that work. Note that the car has no bonnet scoops! The K&N produces no difference, as does no filter in Part 2. It does however allow for regular cleaning. Jsut be sparing with the filter oil.
Chipmaster Monaro