1970 340 Duster rare x car.

you have a hot rodded duster, and a poor one at that, a lot of modifications done to it, nothing on it is the way it left the dealer showroom, that said if its numbers matching it still is worth around $4,000 even with the missing fender tag. BTW Chevy had plenty of 327's and 350's putting out 350 and 375 hp in the 60's look under the hood of most vettes. There were no special X or dusters or 340 engines period...