Vibrant's high efficiency Bellmouth-style Velocity Stacks are ideal for both All Motor and Forced Induction race applications. Bellmouth Velocity stacks help to smooth airflow as it enters your engine, resulting in dramatic airflow improvements and ultimately significant torque and horsepower gains. Velocity Stacks also help reduce turbo lag on turbocharged engines. Constructed from lightweight, 1/8" Thick T6061 Aluminum.