i would try to stay with standard bore if at all possible, if not than the .030 is about the limit you can go on a 351c. personally i would spend the money on a decent set of aussie heads or if you have the closed chamber 4 bbl heads those are the next best. i'd do a hydraulic roller cam swap but keep it on the smallish side especially if you do a stroker and want a decent street car, if you want something more than a good street motor then the skies the limit, especially if you have the 4v heads.