Wilwood Question

Wilwood has a front disc conversion kit for my '68 Barracuda with 10" drum spindles. This kit will move the wheels out .20" which I'd like to avoid if possible. They also offer a kit for '76 Dodge Darts with disc brake spindles that will not change the wheel location. Does anyone know if that's because the '76 Dart with disc brakes wheel location is .20" wider than my '68 Barracuda's? Or is it simply how Wilwood had to design their kit to work with 10" drum spindles?

I'm hopeful to keep my current wheel location by using '76 disc brake spidles and upper control arms with the Wilwood kit for the '76 Dart.