The Challenger's longer wheelbase, larger dimensions, and more luxurious interior were prompted by the launch of the 1967 Mercury Cougar, likewise, a bigger, more luxurious, and more expensive pony car aimed at affluent young American buyers. The wheelbase was longer than the Barracuda's, and the Dodge differed substantially in its sheetmetal, much as the Cougar differed from the shorter-wheelbase Mustang. Air conditioning and a rear window defogger were optional. With 1971 being the sole exception, the front ends of both cars differed from each other in that the Challenger had four headlights and the Barracuda had only two; a trend replicated by offerings from Chrysler's rivals.