Maybe more details needed? Those pads work fine, but they will create a lot of dust and some noise, rotors will wear faster.
Did you replace or lathe the rotors? Don't expect good braking if not.
Did you do a break in? Progressively stopping fast from faster and faster speeds, allowing cool down between each stop?
How is the brake pedal feel? If not firm, you may need them bled, or could even need a new master cylinder.
Fords and Mercurys of that era often had caliper slider corrosion issues, did you take the clips out and remove any corrosion so the pads aren't binding during braking? Often a dab of silicone grease, both under the clips to reduce corrosion, and in the clips to lubricate sliding, is useful.
You could take the wheels off and examine them, consider swapping them out and there is a chance that they might let you exchange them and upgrade to the next better line by paying the price difference, as they have also allowed doing this when it comes time to replace brakes under the lifetime warranty.
