I will warn you,
It can be done, but it also can warp really really bad if you get it too hot.
Most likely you could true it up mostly in the bell and on the cheek, but in my experience it's awfully dicey at high rpm unless you have crazy good welding skills.
Its a much easier and better way to add race gears. Then when you get to the top of the range you're about as far as you could go.