hydraulic clutch in A body

Going back ~50 years the 5/8" MC has been what was used for clutches 90+% of the time. This with pedal ratios in the 5:1 to 7:1 range, which is the most common. It figures that these young OE engineers would screw that up.
Nothing is set in stone EVAR!!! LOL! I also use a 7/8" bore Wilwood WITH A FACTORY VIPER SLAVE CYLINDER. I love it, im not a fan of the "feel" of some factory hydraulic clutch setups, particularly Fords, and right or wrong its just not to my taste. Mine FEELS like a clutch should IMO. Your results may vary....