Estimated Availability: November 28, 2025
This item is currently in production. Thank you for your patience and continued support.
Pricing
All pricing is listed in US dollars.
International Orders: Any import duties, tariffs, VAT, or customs fees are the buyer’s responsibility and are not charged or paid for by Undaunted Manufacturing.
Aerospace-Grade Performance Exhaust System for STIHL 066/660/650
Enhance power and improve engine cooling with this precision-engineered exhaust system designed for the STIHL 066/660/650 Made from lightweight 6061 T6 billet aluminum, a high-strength aerospace alloy known for excellent heat dissipation, the one-piece muffler cover optimizes exhaust flow while helping to keep your engine cooler and extend component life.
Proudly manufactured in the USA and backed by a lifetime warranty, this exhaust system delivers lasting durability under demanding conditions.
Compatible Models:
STIHL 066, 660, and 650
Includes:
One-piece muffler cover CNC machined from 6061 T6 billet aluminum
Spark arrestor screen with aperture size compliant with USFS specifications
Longer stainless steel top screws with vibration-resistant Belleville washers
Dyno Proven Performance
Tested on a completely stock saw with no modifications other than the muffler cover. Results showed a TBD increase in horsepower, and a TBD increase in torque. Performance gains will vary depending on the saw and the level of modification.
Installation Notes:
Apply thread locker on all mounting screws for secure, vibration-resistant assembly
Replacement of the OEM muffler gasket is recommended during installation
Warranty
Lifetime warranty covers defects in materials and workmanship under normal use. Excludes misuse, neglect, or unauthorized modifications.
Estimated Availability: November 28, 2025
This item is currently in production. Thank you for your patience and continued support.
Pricing
All pricing is listed in US dollars.
International Orders: Any import duties, tariffs, VAT, or customs fees are the buyer’s responsibility and are not charged or paid for by Undaunted Manufacturing.
Aerospace-Grade Performance Exhaust System for STIHL 066/660/650
Enhance power and improve engine cooling with this precision-engineered exhaust system designed for the STIHL 066/660/650 Made from lightweight 6061 T6 billet aluminum, a high-strength aerospace alloy known for excellent heat dissipation, the one-piece muffler cover optimizes exhaust flow while helping to keep your engine cooler and extend component life.
Proudly manufactured in the USA and backed by a lifetime warranty, this exhaust system delivers lasting durability under demanding conditions.
Compatible Models:
STIHL 066, 660, and 650
Includes:
One-piece muffler cover CNC machined from 6061 T6 billet aluminum
Spark arrestor screen with aperture size compliant with USFS specifications
Longer stainless steel top screws with vibration-resistant Belleville washers
Dyno Proven Performance
Tested on a completely stock saw with no modifications other than the muffler cover. Results showed a TBD increase in horsepower, and a TBD increase in torque. Performance gains will vary depending on the saw and the level of modification.
Installation Notes:
Apply thread locker on all mounting screws for secure, vibration-resistant assembly
Replacement of the OEM muffler gasket is recommended during installation
Warranty
Lifetime warranty covers defects in materials and workmanship under normal use. Excludes misuse, neglect, or unauthorized modifications.
