w2 heads

I just got my 68 barracuda out for body and paint yesterday, know me and my dad are starting the motor. Its gonna be a strip happy car but also streetable.Ive been reading SO much on what heads to use for our 340, and it all came down to w2's. I keep reading about people machining down valve seats. what would have to be done after buying w2 heads? I was considering porting to get closer to 300cfm. Does anybody have + feedback on the w2's? or is anybody running different heads that they would suggest?
- Thanks