The model name of these units delineates their size - the once-commonly used 4-71 and 6-71 blowers were designed for 71 series diesels. Current competition dragsters use aftermarket GMC variants similar in design to the 71 series, but with the rotor and case length increased for added capacity; hot rodders also use reproduction 6-71s.

Roots blowers are typically used in applications where a large volume of air