The 273's can ge a little more spendy to do. The pistons are more money that just off the shelf 318 pieces. The cam's and lifters are more because they aren't a generic off the shelf part. The rest is really the same. Pistons from Egge and Kanter (if they are still in business) and cam and lifters from Isky, Racer Brown, or have one ground by Oregon Cam are some choices.