Actually I've owned two 66 Valiant 2 door sedans over the years, so this reveiw will contain comments on both cars.
The Valiant is a great poor mans project car. Lots of Barracuda parts fit: seats, gauges, trim ect.
If you look around there are many upgrades, even of the base slant six, which I have.
This car has an overdrive four speed from a later Aspen, and will be getting disc brakes from a later Dart in the near future.
While the handling was good for a mid sixties car it has been upgraded with front and rear sway bars from one of the big catalog sales firms. These are the best money you can spend on any older car, think about it before starting any hot rod work.
The slant six may be one of the most durable engines ever built. Mine has taken many modifications (4 bbl, headers, head milling) and gives no problems.
Great runner and while not a Mustang, or Challenger, gets lots of looks on the road.