Change a 904 to manual valve body

Have a rather butchered 71 Dart. Long story. Original motor was a slanty, swapped for a 360 before I purchased. Kick down linkage was MIA on purchase and I wasn't aware of it (I know, I should have checked), so some miles were put on it, probably less than 100 but enough that I knew it wasn't right. Hoping the trans is not trash at this point. Tried using a Lokar cable, but could not get the adjustment anywhere close, always too much slack on both ends. Without going to steel linkage that I would have to find for this car, would a manual valve body be an option for a daily or should I just try and find a full linkage set and fight it to get it set up right?