I would expand your search the include builders such as Southern Automotive, Brent Lykins, Keith Craft and others.
The "Roush" name carries a lot of weight with some buyers but you can get more for less elsewhere. If the name is not worth the extra cost to you there are good values in Windsor 427 strokers to be had
Call Dennis at Olthoff Racing to purchase and install the powertrain, call me to buy the chassis
Dennis can also guide you through the NC regisdtration process.