Are the bolts seized in the clips if not take them out soak the area with penetrating oil of some kind let sit and try to work a screwdriver or small pry bar around the edges if that doesn’t work you might try some heat to heat it up nice and hot to try and expand the pieces to break rust free If that doesn’t work you might have to sacrifice one or the other You could cut one up and scab a piece back in after the fact My 69 I had to replace rad support the mount hole was rusted thur and sitting on sub frame Good luck
