Abstract: A blocker-clutch assembly (10) includes an openly porous, pyrolytic carbon composite friction material (74) configured for optimum performance and, therefore, prevention or substantial prevention of nonsynchronous engagement of positive clutch members (12,14) due to premature unblocking of blocker tooth ramps (48-54). The composite friction material is formed to be resilient in direction normal to its friction surface (76b), is cut into segments (76), is bonded to a frustonconical surface (62) in a manner preserving the resiliency and with the segments circumferentially spaced apart, and is configured to control engagement force thereon in a range of 150-300 pounds per square inch (10-20 Kg/cm.sup.2).