In this build you will have tons of AP actually over 600 AP. I found out try to win your lane very fast because roaming as Evelynn destroys. Your burst is so high and your a very good tank killer. Why are you a great tank killer? Well your ult does a percent of the enemy's health so if they have 3,500 hp and you ult them you will destroy them. Also you deathfire grasp does 15% of the enemy's health. So if you do not kill them you will defiantly do tons of damage to them. Most people think Evelynn is very under powered but if you try this build trust me you will change you mind.

Here are the Pros and Cons of Evelynn

Pros
You will destroy everything including tanks
Squishy people will not stand a chance
W makes you have good chase ability
You have so much AP
She is pretty easy to play
A lot of pushing power
Can escape decently
You can carry


Cons
You are pretty squishy
You are really not that great early game
Ranged will screw you up (at the start)
You are a glass cannon