The first one is either a General Dynamics Propulsion System Demonstrator that they built to compete with Lockheed Martin's design, to win the contract to build the Expiditionary Fighting Vehicle (amtrac that can go really fast in water).
The second is an XM-579-MTV (Marginal Terrain Vehicle) designed around Vietnam timeframe in order to drive through swamps and stuff.
The only vehicles that don't run in the immediate vicinity of the museum are the M60A1, M103A2 (no engines), and M109A3. Everything else runs.
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