You are absolutely right Rip. The Galaxie was too big. The Thunderbolt had to have been the Fairlane. Look at the body on the one you show in your post and compare to the one I posted. The one I posted is the Galaxie, the big car, the one you posted, both the white one and the maroon one are Fairlane 500's. Key words here are Fairlane and Galaxie.
Now if Ford decided to call 53 of their Fairlanes Thunderbolt Galaxies then that certainly was their perogative but the Fairlane is the smaller chassis and the one raced in drag racing. They raced the Galaxie in NASCAR.
Mark