Few production cars let all four doors swing open with no center pillar in the way — Lincoln built one on purpose, then added a hidden safety interlock most owners never noticed. This powder blue 1964 Continental is one of just 3,328 four-door convertibles Lincoln built that year, vastly outnumbered by hardtop sedans. Under its long hood sits a 430 cubic inch V8 good for roughly 320 horsepower. Here’s what makes this body style so hard to find today.