I use a K&N 14x6 air cleaner on the dyno. No power loss at 900+ hp. So if you have room for a big air filter then you should run one. Not only does it keep junk out of the engine but it can also help improve the air flow to the carb. An open hood scoop can have a lot of airflow over the carb which can disturb how the air goes into the carb. The air filter element slows down the air and helps it make the turn into the carb.