Here are some of the specific modifications that would be required for this swap:
* Fuel system: The 1997 Mustang V6 uses a fuel injection system, while the 1968 Mustang fastback uses a carburetor. The fuel tank, fuel lines, fuel pump, and fuel injector will need to be swapped out for the corresponding parts from the 1997 Mustang.
* Exhaust system: The exhaust system of the 1968 Mustang fastback will need to be modified to accommodate the 1997 Mustang V6 engine. The exhaust manifold, exhaust pipes, and muffler will all need to be replaced with the corresponding parts from the 1997 Mustang.
* Electrical system: The electrical system of the 1968 Mustang fastback will need to be updated to accommodate the 1997 Mustang V6 engine. The alternator, starter, and voltage regulator will all need to be replaced with the corresponding parts from the 1997 Mustang.
* Engine compartment: The engine compartment of the 1968 Mustang fastback will need to be modified to accommodate the 1997 Mustang V6 engine. The engine mounts, transmission mount, and driveshaft will all need to be fabricated to fit the new engine.
In addition to these modifications, there may be other minor modifications that are needed in order to complete the swap. It is important to consult with a professional mechanic before attempting to perform this type of modification, as it can be complex and time-consuming.