Almost all of the engine parts are available at rockauto, just not in a kit form. oldmoparts.com has parts too, no kit, with some parts rockauto doesn't have and other parts that may be cheaper.

Kanter and Egge are way overpriced.

BTW, since no one would hot rod a 230, Offy sells a dual carb intake, Summit stocks it

http://www.summitracing.com/parts/ofy-2691/overview/make/plymouth

Never assume