Bare housing, blasted and painted on ebay "buy it now", they are asking $300., that is a bit steep, but they are getting hard to find.
Cheaper to buy "B" body, a little wider and you'll need to re-locate the spring brackets.
The '68-'70 b-body rear is 3" wider axle flange to axle flange so you would need a wheel with 1 1/2" additional backspacing. The '65-'67 b-body is 2 3/8" wider than the a-body so if you used one of them your wheel backspacing need to be 1 3/16" more.