Add hotter cam or Add hotter head ?

Heads that flow 10-20+ cfm more in the .1-.400 will show more power increase/lower et with the existing running gear/convertor.
More flow...manners stay the same...power just goes up.
Not talking about the wrong head..."too big" but the right head.
Did this. Heads alone can bring it up a ton.
Can you also have stock ish ca timing and higher lift , sure..but the way they flow..its not much gained without changing the cam timing events and lengthening them .which changes the manners and 98% of the time requires more gear or convertor.