Degreeing in the camshaft gives an important base line

Not many novices go to this length but it is the best sure way of knowing that all the components you have bought are timed correctly. If they are out, for what ever reason, then it leads to all sorts of problems when up and running and you will be thinking its spark or fuel and you will end up chasing your tail for days with no results.  So if you are dead sure the engine insides are right ie. having porperly checked them, then there is only spark and fuel left to tune once up and running.