just remember to ask how its on the valvetrain. some rollers ramp up fast and its hard on the valves and springs. they usually make a little more power but in decline in longivity. If they dont know if it is, and they should know. rule of thumb is by the valve adjustment. Most hard hitting roller's will have loose clearance's on the valves 28 to 30 and above. smooth action rollers are tight 22 range. just a lil guidelines.