It only makes sense that if you have your engine out of the car that you replace the timing chain.
The chain controls the timing of the camshaft and even a slight amount of wear or stretch can result in poor engine performance.
There are several varieties of timing 'chain' - single, double (2H4905) or toothed belt, check yours before ordering.
These are Genuine AE HEPOLITE (Federal Mogul) and the favoured endless type, double row chain.
For competition use, see 2H4905.
For genuine duplex gears, see C-AJJ3323.