Which side cover to use

hi, I looked in old mopar race manual , concerning 4 speed trans. mopar wanted the ball/detent used for racing , was for slick shifted trans. the ball/detent is more positive does not hang up in two gears at once. the lever style is same used by general motors. I remember many GM guys missing gears with those levers . the ball /detent can be modified to increase the travel of the slider for better engagment of gears. I ran the ball /detent style always. just food for thought!!