This pushrod length checking tool is specifically designed with ball and cup ends for use with Chrysler engines. An easy and economical way to measure for proper pushrod length for rocker arm geometry and seating position, which prevents the rocker from turning sideways and/or wearing out the valve guide. Turn the nut on the adjustable end until you have reached the desired length. Remove the tool and measure with micrometer. Continue until all valves have been measured.