Porting BB heads

I'm looking at porting a set of BB heads for the 451 I'm building. I have a set of 346 and 906 castings if I remember right. Since there isn't really much difference between the castings I will probably go with the set that looks the best.

I've done some reading and researching but, since this will be my first set, I want to get as much information as I can.

In your opinion what is the best way to go about porting? Where should I concentrate? What are the 'proper' tools for the job?