Front disk brakes not releasing.

Kendog 170 said
if it's a disc MC do you have the spacer between MC and Cowl panel

BPTracing said
new power disk brake setup from Right Stuff on my 67 Dart.

He installed a power brake setup

The pushrod from the booster to the MC is adjustable.

My money is on the piston is not being allowed to return fully due to incorrect push rod length.