I think that if you decide to do an original restoration of the car, rather than make it a custom or resto-rod, I think you should put it back as a Gran Coupe, which was kind of a "luxury" Barracuda, with a nice interior, and take off the billboards. The Cuda is a different model (kind of a sport/performance model) with engines available from 340 all the way up. The largest engine you could get in the Gran Coupe was the 383. Of the 16,159 Plymouth Barracuda cars made in 71, only 1,298 of them were Gran Coupes. Don't know how many Gran Coupes were 383's, but I'll bet it is rare. (I am not that knowledgable, but know where to look it up). The Barracuda is the base model which could get up to a 383, like the Gran Coupe.
Matching numbers is a plus, but less important in Mopars than say old Corvettes. But the 5th digit of the VIN, which tells the engine, IS important. A slant six letter (B or C) makes the car worth less than a 383 (L or N).
If it were a 318 Barracuda I would say don't spend a lot of money restoring it, but a big block Gran Coupe and a 71 to boot is worth it, as long as it's already in pretty good shape. The replacement block isn't a reason not to so it, particularly since it is correctly dated and the right engine.
