In 1968, Chrysler built 50 each Plymouth Hemi Barracudas and Dodge Hemi Darts. They were purpose-built drag race cars straight from the factory. They weren't street legal, but they met the NHRA requirement that a car must have been a production model with at least 50 made to be eligible to race in Stock or Super Stock. The Hemi Cuda here is an excellent example! http://www.barrett-jackson.com/Events/Event/Details/1968-PLYMOUTH-BARRACUDA-SUPER-STOCK-116812

Over the last few years, Ford, GM and Chrysler have gotten back into the business of manufacturing purpose-build cars for drag racing. They too are not street legal, and the annual production runs have been limited to about 100 for each model and year, eligible to race in either Stock or Super Stock depending on what you add to it when you order it and/or after you receive it. Those are the Mustang Cobra Jet, the COPO Camaro and the Dodge Challenger Drag Pak.