Problem with brake swap.

I think you should first verify that the front calipers aren't seized, as that was a common problem with the "plastic" pistoned calipers.

Jack the front wheels off the ground, apply brakes and see if a wheel can be turned by hand. Spin a wheel and apply brakes and see if the front brakes will stop the wheel, then try the other side.

If the brakes will not apply and stop the wheel, with the brake pedal still applied, crack open a bleeder on either side to see if there is fluid pressure at the caliper.

If there is pressure at the calipers that won't apply and stop the wheels, the caliper is likely seized, and needs replacement.

hope it helps . . cheers