When your looking to maximize your valvetrain's performance, look no further than the Heavy Duty Series from Harland Sharp. Designed for high spring pressure and high lift geometry, Harland Sharp's Heavy Duty Series can withstand over 1000lbs of spring pressure. The wider body design is engineered to provide increased strength and longevity to your engines valvetrain. Independent tests have shown the Heavy Duty Series body can withstand over 10 tons of pressure before showing signs of stress. These rockers are for use in hardcore racing applications and highly modified performance engines. Rest assured though, the Heavy Duty Series from Harland Sharp will keep you running ahead of the competition.