I hate the word 'synergy' as IMO it implies a bunch of corporate crap, however , for lack of better term, There would be ZERO synergy in merging these 2 cultures. The Parts bin swapping & cost cutting would produce a dearth of worthy ideas & more likely than not , bland uninspired vehicles.
Ford should have saved $20 mil from the Astronaut CEO , Nix Mercury ...develope rear drive V8 sedans ....have sane union contracts ...streamline operations....it's not rocket science.
Besides GM is just another Lumbering Lethargic Beauracratic Organization....It's Like Merging Oprah & Rosie Odonnell

& expecting angelina jolie