FYI, Pinto unibody does not have really stiff front frame rails. Cutting fenderwell out in the wrong way can greatly weaken the entire 'box' that stiffens up the whole thing. The shock towers and further forward wells provide stiffness to locate the frame rails further as far as movement under load. The front radiator support structure reinforces all that to make the 'box'. That allows for lighter thickness front frame rails that cannot stand alone by themselves unlike a true full frame car that can.
You CAN cut there if it is done intelligently but you'd best have some ideas as to load bearing and things like that.