the main question is...... what kind of driving do you mostly do..... like are you a stop light to stop light quarter mile guy like my self, or do you want a car with a smooth idle that is suited for highway driving, or do you just "drive miss daisy" around??? that will dictate the lobe seperation and lift and durration. also are you converting to a roller or staying flat tappet? and do you have valve reliefs cut or cast into the pistons?