that the Mach 2 used a Mustang convertible platform (stronger with the extra inner rocker panels and torque boxes and had the fuel tank in the tranny hump that was now empty.
Lot's of neat stuff in Ford advanced in the mid to late 60's. I saw some cool stuff in the early 80's when I knew Bill Stuef at Ford. He went on to do the aluminum Taurus and some other neat stuff there. I would go to the "scientific research building" and once Bill got me inside I was able to wander and see a LOT of stuff I should not have been allowed near!
Rick