Use this insert for :  Carbs-  Throttle bodies- Bugcatcher- Birdcatcher- Buzzardcatcher - Hilborn 4 port or Shotgun  12.25" 

TBS Race Inserts are crafted from billet aluminum in an array of sizes.  

Meant to change when boost is activated, a smaller opening boosts quicker and a bigger opening produces more boost on the top end.  

A quick way to tune your blower at the track, these inserts are available only for the race series blowers.

Available in:

7.5 inches-   #2125

8.5 inches  #2124

9.5 inches  2123

10.5 inches   Big and Ugly and Carbon  Hats  # 2122

12.25 inches -  Bug catcher , Birdcatcher, Buzzard   # 2121