Muffler. PART NO: A-AR89594. Vertical / Oval Body - 8" X 11 1/2" Shell Dimension. Muffler Has Curved 1 1/2" O.D. Aspirator - Ref: G. Dim A (1)A: 3 1/2" INLET LENGTH Dim B (2)B: 3 15/16" INLET I.D. Dim C (3)C: 30" SHELL LENGTH Dim D (4)D: 5" OUTLET LENGTH Dim E (5)E: 5" OUTLET O.D. Dim F (6)F: 38" OVERALL LENGTH. . MODELS: John Deere TRACTOR: 8440 John Deere TRACTOR: 8640.