It is an H code car whether it has the original engine or not. Whoever owns it is always going to bring up that fact that it's an H code. So I would say it does have more value then a c code slant 6 car.
True, but how much more value? $100? $1,000? $5,000? Quantifying that value is almost impossible. The fact it doesn’t have the matching engine means that incremental H code value is probably closer to the $100 or $500 premium range compared to a C code slant car. Heck, a mint or well preserved C code car with a 340 transplanted into it might have similar value to this H code with a non matching 340 drivetrain? And that C code car will probably cost less, even after dropping a 340 into it, compared to sinking the $$$ into restoring this H code Dart?