Have you considered slightly changing the gear ratio? If you choose one that was available from Ford at that time and get the matching ID Tag, you can leave the Engine as is and still boost your performance. You'll have to have a new Warranty Tag made as well to reflect the change.
Two things to consider, if you have an Automatic Transmission, should a cam change alter the Engine Vacuum significantly enough the Transmission may not shift correctly and if you have Power brakes it may suffer from a lower Vacuum as well. The other is, will your current Braking System be up to the task of stopping your car with an increase in Engine Power?
If you do opt for a cam change, work very closely with the Machine Shop and make sure that they can cope with changes to the Cams Lift and Duration, how it affects Piston Clearance, how does it change the engine breathing and will all of this require changing the Intake Manifold, Carburetor and Exhaust? If you change the Engines ability to breath, you may also need to change its ability to draw air through the Carburetor and its ability to get rid of it through the Exhaust. If these do not match you may find that the new cam actually lowers your Engines Performance.
I'm with Brian, leave it stock. You may find that if the Machine Shop can properly Balance and Blueprint the Engine, you'll pick up enough power from doing just that alone. It's still stock, will increase Engine Life and you'll have your performance increase as well. Don't forget about you Brakes; stopping the car is all important!
Hope this helps.
Ray