Made by RevTech and sold by Custom Chrome. Part number 659617. Sold in pairs. These are high performance nitrited exhaust valves with 1.610 head diameter. These are .045 inch larger than standard Twin Cam Exhaust valves, and would help exhaust flow. The material and design of these valves are superior to stock OEM valves from Harley Davidson. These valves come in the RevTech 100 and 110 high performance engines and replace exhaust valves in 80 inch evolution motors made from 1984 – 1999. Use as upgrade on 1999 – 2004 Twin Cam motors. Normal valve stem length and diameter. Retail price from Custom Chrome is $24.95 each. Nitrited valves out perform chrome or stainless valves. This listing is for 2 (two) exhaust valves.