If you have to ask them don't even try it. They are a difficult task at the best of times and if you don't set the timing marks correctly you will be buying a new motor. It's whats called an interferance engine
You can set the base timing by ear good enough to get it running. But you will have to have a engine scanner to set the timing correctly. The timing is controled by the PCM. POWER TRAIN CONTROLL MODULE.