A little advice please

I took some measurements and a 5.9 Cummins will fit with ease in the Galaxies engine bay. Despite all the unexpected nay saying I received I am gonna be moving forward with my Cummins powered 1968 Ford Galaxie 500XL Fastback. I wouldn't do it if I just intended to sell the vehicle upon completion of restoration, but I plan to use it as a family daily driver to avoid putting so many miles on my 1964 Dodge Dart 270 with a slant 6. I figure if I am gonna drive a asphalt boat might as well make sure it has the power and reliability of a Mopar with the gas economy of a newer sedan that only a diesel can provide in such a situation.