The timing chain on the 6.2L engine will have slack or deflection. It can be measured whenever the front cover is removed from the engine. This is done by using a dial indicator mounted to the front of the cylinder block with the plunger contacting the timing chain between the two sprockets. The chain can be deflected outward a maximum amount with finger pressure on the internal side of the chain. The dial indicator can then be set at zero. The chain can then be deflected inward using finger pressure on the external side of the chain. The total indicator travel can be noted. On a used engine, the deflection cannot exceed .800″. If it does, the sprockets and chain must be examined for wear and replaced as necessary. The timing chain deflection with new parts cannot exceed .500″.