Green’s Dictionary of Slang

1. (US, a low bar-room, a ‘dive’; thus US black) a dancehall.

1953		L. Durst Jives of Dr. Hepcat (1989) 3: The ark is foggy and each and everybody begins to reel and rock, yes the joint is naturally jumping.
1981		McKee & Chisenhall Beale Black & Blue 28: [A] posse that swept down on a black desperado [...] in a South Memphis ‘ark,’ a Memphis name for a black dive.

2. a car.

1969		in Current Sl. IV:3–4 (1970).
1981		J. Wambaugh Glitter Dome (1982) 85: The happy Ferret leaped into the nark ark as the Weasel yelled, ‘Let’s get on it!’.