The Dodge Dart is best known as a humble economy car, but the 1968 Dart GTS featured on this episode of “Jay Leno’s Garage” shows the compact Dodge had a sporty side too. Instead of the inline-6 engine many Darts left the factory with, this car has a 383-cubic-inch V-8 with a 4-barrel carburetor. The same engine was used in the more popular…