That is an easy theory to prove . Pop off the valve cover, and measure the lash. You will find one of two conditions; spot on, or gaps need to be adjusted. Factory setting: intake 0.010”, exhaust 0.012” with engine at operating temperature.
When checking gap remember the first three cylinders intake & exhaust valves are positioned E-I, E-I, E-I. The last three cylinder’s valves are I-E, I-E, I-E.
