hughes engines is the only place that i know of that sells a complete kit.
you can also just buy the aluminum pan on ebay and buy all your own gaskets. i know some people don't like the gaskets that come with the hughes engines kit.
some people also recommend replacing the water pump, timing chain with a double roller timing chain and installing a tensioner. i don't know the best place to buy them but mopar part numbers are
P5007709 Timing chain tensioner
P5249267 Double roller chain and sprocket set