So far I've found detail master and model car garage to make a few items. Hood tethers, hinges, air cleaners, etc. Some things will have to be scratch built I guess. I did find an updated nose for the Dodges, a pretty nice resin piece that I got for around $10.
Watch out for the Nascals though, I was disappointed with the detail/quality of the printing, the car I'm doing is going to be heavily detailed and the decals just won't cut it. I'm hoping I'll be able to make my own with my graphics programs and color printer.