Ford used a couple different racks back then. One was a Ford built unit and the other was a TRW unit. They had different power steering fitting sizes and may have different mount spacing as well.
You probably need to identify which unit was on the car first. Also identifying who's Mustang II IFS unit is on the car might help too. There are a lot of bozo's making Mustang II IFS systems and all are not created equally.
"Congress will eventually do the right thing, but first it must exhaust all other possibilities." - Ronald Reagan