Modern technology, for your classic 911. Using wave cancellation to attenuate unwanted sound frequencies, while enhancing scavenging via pulse tuning, the Bisimoto Spec Pulse Chamber for the Porsche 911 SC,911 and M491/M490 (ranging from 1978 to 1989, 3.0-3.2L powerplants) is an excellent choice. The result, a deep, throaty sound and documented 11-17 horsepower improvement with no other modifications. Unlike any muffler on the market, with over 15 pounds in weight savings compared to stock units. Made in the USA, from pure stainless steel, at a feathery 5 pounds.
For additional sound reduction, a new optional "arrestor" is included for an amazing 18+ decibel reduction in sound, without any horsepower penalty. Fully removable, with a 6mm bolt, for that race inspired tone, when desired. Modern day science, for your classic Porsche.
Available in gorgeous stainless steel. Option exists for a hanger to allow for bracing, if desired.