Flowmaster HP-2 Series Muffler - 2.25" Inlet, 2.25" Outlet - 18" Case - 409S Exhaust Port Block-Off Gun-drilled idler shaft & magnesium

Gun-drilled idler shaft & magnesium filter mount are standard

Weld in 1/8" NPT female threaded bung

1955-1955 GMC 280-22

Intake runner volumes of 200cc

4340 Crank

Flowmaster HP-2 Series Muffler - 2.25" Inlet, 2.25" Outlet - 18" Case - 409S Exhaust Port Block-Off Gun-drilled idler shaft & magnesiumConstructed with an 18" long, painted 409S outer shell, and 409 Internal components. Available in 2. 00", 2. 25", and 2. 50" inlet outlet sizes. The 409S HP 2 mufflers have a case length of 18 inches and a 4. 00 X 5. 50 inch width. Due to their Cool Shell Technology they can be placed in virtually any location under the vehicle. The 409S HP 2 mufflers feature a painted 409S outer shell, and 409S internal construction. Available in 2. 00, 2. 25, and 2.