D Dart Cam Specs

I'm new to the early A's and have a question. What is a D-dart? Was it an engine pkg. offered for the early 273 Darts? (Higher comp, Better heads, 4bbl, and high flow exhaust manifolds)? I'd be interested in any info on this engine.
Chrysler built 50 cars to compete in NHRA's D/S class. The cars were 1966 Dodge Dart GT's with 275 horsepower 273 engines. Just do a search on here for D/Dart or my member name ddartdude. You'll find out what you might need to know. Also do a google search for ddart2. We have a website on them.