Based on my experiance I think its safe to say that your 17" tire will probably be 1 to 2" taller than the stock 13" tires. If you have springs already I would just us lowering blocks they are cheap and easy to install and uninstall if you don't like them. They also come in many sizes.
Keep in mind with the 64 dart the car will look lower just by installing 17" wheels. The top lip of the wheel will now be 2" higher probably even with the fender or up under the fender a little.
Last you might want to make sure nobody added a overload helper spring to your car that might be easly removed for lowering the back of the car.