How many CURRENT owners of real '74 360 Duster 4 speed cars on here?

Honestly counting on anything to be worth more, especially in 20 years is just plain dumb. Car or other investment.
Nobody can predict the future, just look at the hit these 'investment' cars took over the past years since mid 2006.
Will the 1974 360 cars ever be worth as much as the 340 cars? No.
While I prefer the 1973-74 Dusters, especially the 1974 Duster 360s, it's no secret the greater majority of Mopar people have no love for the later model year cars. Unfortunately it's the greater majority that help drive the market, thus the values.

In all honestly to fully restore ANY muscle car right now is a basically losing proposition.