I am not a great fan of these types of aftermarket air boxes, quickly conceived with the idea of selling the idea of “cold air intake” and “forced induction”. Both have their place, but I am more of the thought of how the air enters the air box, how its distributed and how the airflow is within the ‘box and presented to the carbs/trumpets is much more important. Yes, you may well gain some hp by having cold air coming into the air box, but if that is lost (hp) due to poor design within the air box, what is the point? You have a highly designed air trumpet to pull as much air in as possible but yet how the air gets to them I don’t see being thought about in these aftermarket ‘boxes.
If you look at some of Nissan’s stock air boxes for their models from the early 1960’s into the 1970’s, there is some thought and design that has gone into them, and for a reason. Yes, our L series are running bigger carbs and are more performance orientated, but it doesn’t mean design has to wash over what has come before. Nissan would have put a lot of time and Yen designing their air boxes and for they did it for a reason, so why can’t we? I know I have.