Marine Muffler. Gibson Bullet Marine Mufflers were tested up to 1200HP with minimal or no Power loss. High Quality Stainless construction. OEM style transom mount. Straight through design. Utilizes water to dampen the Sound. These silencers were specifically designed for Large displacement motors such as 500HP 502 525 525SC 575. and up to 1 200hp. Easy bolt-on installation. The Gibson Marine Mufflers have proven to reduce decibel ranges within and to surpass the 88db limits required by the California SAE J2005 Motorboat Sound Law without compromising Power.

• Footnote - J2005 Sound Ordinance Approved.
• Finish - Polished T304 Stainless.
• Dimension - 25 x 11 x 11 in.
• Item Weight - 18 lbs.

• Lay out Mufflers and make sure you have all required tools and parts. Now remove your 4 in. Exhaust tip and rubber flaps.
• Gibson has provided gaskets to use between the muffler and the Transom of the boat. Use this gasket as a template to mark holes. Mark holes so that they are at top left and right and bottom at six o'clock. This will also make the Gibson logo on top at twelve o'clock.
• Drill holes in transom for quarter - inch studs with 1/4 in. drill bit.
• Slide gaskets over studs on muffler. Slide muffler into Transom and add liquid soap to hose. Add anti-Seize to nut with washer until you feel resistance or like it has bottomed out. (Do not over tighten or force!).
• Now that everything is tight re-install your factory style Exhaust flaps.