Just a precaution on rebuilt 904 transmission

I'll try to keep this short. I bought a 318 with a 904 to put in my Rambler, yes an American Rambler....anyway I rebuilt the 318 but not the 904 as the previous owner said it was good. I changed fluids, and filter and set the kick down attached to Carter AFB....well it lasted about 50 miles. I ended up replacing the transmission with a rebuilt TCI unit. My question is...I want to make sure I have the K/D cable hooked up right before I drive off, so I already bought a Edelbrock Mopar linkage arm to attach to the carb to make sure the ratio is right, seemed like it was before?. To adjust with a cable do I just make sure at WOT the cable is pulling the trans arm all the way open? What about at idle....no free play? Picture of the vehicle.20200222_124328.jpg20200222_124310.jpg