273 rocker info please

guys , im starting with bare x heads .... Dave is providing me with the 273 rocker arms and i have the gr00ved shafts also.
Im not trying to re-invent the wheel or complicate anything or squeeze out every last HP but since the heads are bare already I figure why not go with the better option.
My goal is to build a strong, reliable 340 with good machining and good matched parts....