
Manley's valve spring and retainer kit for the Nissan Patrol TB48 lists a maximum lift of 0.550" and specifies use of factory valve locks rather than supplied locks. The kit includes matched springs and titanium retainers intended to provide consistent valve control under higher lift applications and to support valvetrain rebuilds where factory locks are reused.
Manley Nissan Patrol TB48 Valve Spring and Retainer Kit (Use factory valve locks)