Plot: One of the most common valvetrain upgrades for pushrod-style engines is roller rocker arms, which are often said to increase horsepower through reducing friction. But is it true? You’ll find out on this episode of Engine Masters presented by AMSOIL, as we use a 7,000-rpm, small-block Chevy to test stock-type stamped-steel rockers, roller-tip rockers, full rollers, and full rollers with a ratio of 1