Why open collector? You will need pullups then..
BTW, I beware you about myself not having build a discrete Hbridge controlled by a L297, I'm struggling with a one side pcb L297+L298 design for the OpenSource CNC and a L297+L6203 design for my own pleasure by now. So plz do not trust blindly in me, if any release of magic smoke to the atmosphere occurs and is not from my own semiconductors I will feel very guilty
The main info I handle about using discretes is from the ST datasheets. In the datasheet of the quote (fig 17 by example) you need a negate signal for every phase, so I think you will need a 74LS04 too..