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 - 17 lbs.

• Lay out Mufflers and make sure you have all required tools and parts. Now remove your factory external rubber Exhaust flap. Do not damage or throw away you will re-use it later.
• Measure 3 in. towards the transom and mark. It is important that the tip does not slide on any further than 3 in. nor any less.
• The Gibson logo must be facing upward with the clampless portion on the bottom side of the muffler.
• Before you tighten down the mufflers check for proper clearance from the swim steps steering bars out drives etc.
• Install the bolts into the clampless portion of the tip. It is recommended that you use anti-seize on the hardware. Using a 1/2 in. wrench and socket tighten down the bolts. Tighten down the bolt closest to the muffler and then the one closest to the transom. Tighten the bolts until you can no longer rotate the tip. Next tighten 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.