How do you adjust rocker arms on a 2.5 87 Chevy Celebrity?

To adjust the rocker arms on a 1987 Chevy Celebrity with a 2.5L engine, first, ensure the engine is cold. Rotate the engine to align the timing mark on the harmonic balancer with the "0" mark on the timing cover to set it at Top Dead Center (TDC) on the compression stroke for cylinder #1. Loosen the rocker arm adjusting nut, then tighten it until there is no play in the pushrod, followed by an additional half to three-quarters of a turn. Repeat this process for each cylinder, ensuring proper adjustment for optimal valve operation.