Abstract: A centrifugal blower assembly including a blower housing having a scroll wall defining a blower chamber, the scroll wall extending circumferentially between a cutoff point to an end point defining a blower circumference, the blower housing further having a surface adjacent to the cutoff point; and a modular cutoff configured to attach to the surface of the blower housing, the modular cutoff having an abutting surface and a cutoff surface configured to extend the cutoff point of the blower by the cutoff surface to an extended cutoff surface. The abutting surface of the modular cutoff further includes an attachment feature configured to mate to an attachment feature of the blower housing.