With engine builders striving to build higher amounts of combustion pressure through increasing supercharger and turbocharger boost levels, Manley Performance has the answer for these high exhaust temperature environments with its expanded Extreme Duty valve line. Originally developed for supercharged, nitromethane-burning engines, Manley’s Extreme Duty valves —manufactured from the company’s unique XH-432 XtremeAlloy (Inconel material and proprietary heat-treat process) have been the mainstay of drag racing’s top Pros for decades.
In addition to stocking application-specific models for most popular engine families, Manley offers Extreme Duty valves through its Gen II program for custom valve orders. Through this program, Manley maintains an inventory of “blanks” in popular stem diameters and finishes them to the desired length and head specifications.
Other attributes of Manley’s Extreme Duty exhaust valves include swirl polishing, chrome stems and hard tips. They are engineered to operate in temperatures exceeding 1600° (F).
Manley Performance manufactures valves from no less than five stainless steel alloys, plus titanium, and a complete lineup of ancillary valve train components (locks, retainers, springs and seats). For details visit or call the company’s tech line at 732-905-3366.