Our EMI Thunder has been modified to work on the new 496 MAG and 425 MAG HO Mercruiser engines. We are proud to offer a complete kit with specific mounting locations for all necessary brackets and we also supply new oil lines to make your installation as simple as possible. Our system does not require remote installation of any part, everything stays on the engine. We went to great lengths to make our exhaust easy to install. We found that these engines need a good exhaust system like EMI Thunder. On most applications EMI Thunder increased performance at least ten percent on both the 375HP MAG and on the 425HP MAG HO. During our factory tests we found unbelievable performance gain in the mid-range on our test boats