Curious how much lettering you are going to be doing? If you put the Roush name on the car that could be a sticky situation of the right person saw it. Use of the name and likeness of old cars are copyrighted by Roush Fenway as far as I know.
Its not a exact clone by no means, no more then any "donk" with nascar garb,etc slathered down the side. I could see a issue if it tried to be passed off for real but it isnt by any means,wants or effort