I use a plastic dead blow hammer to hit the rocker arm above the valve stem. As I am striking each one, I am watching for rapid rebound of the valve and a soothing clunking sound of a healthy valve contacting a healthy seat. You will need to manually turn the engine over a few turns in order to test all of the valves, as some of them will not be on their seats due to the camshaft.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission