Single piston caliper to dual

My 68 cougar has factory single piston front dick brakes.

How do I get dual piston front brake calipers

Like the 67 .

Do not want :

Bare , wildwood , Brembo .

1968 Mercury Cougar Kelsey-Hayes 4-piston front disc brakes .

But i read that the Hayes was on 67 not 68.

As I said mine 68 has the single piston .

Read the Kelsey-Hayes kits changes the spindles ( drum ) but mine already has disk.

Will I still need to change the spindle, are those different from mine..

From what i understand.

change the the drum to disk .

you have to Change the spindle to go disk .

Help , please.

Went to a bigger and more hp engine .

That’s why I want dual or it’s called 4 piston.

Help please .