You are talking through both sides of your mouth.
Seems as long as you don;t have to invest effort, its alll good. (porting your heads)
Do not use 1.6 valves on those heads on a 305. just 1.50' but the 1.94's will help (with porting)
You can simk all the money you want in it, but the poer of the 305 will be limited by the stock heads.
Money won;t fix that. But effort, will.