Mine wasn't a muscle car either when it left the factory. Just a 273 727 so nothing special. If it was a 273 Hypo or a 383 then yes it would be worth a lot moreI have most everything I'm missing the build sheet and a few other things but I have the registrations on everyone that owned my car since new so that helps.
But it's a Scamp not a Muscle car so value is a bit smaller than something like your Cuda.