The front calipers are easy to replace and can be found for about $60 each. The trouble with locating them is that the 230 was a rare car in 1971 in the US, so you need to find an interchange manual, or ask someone here, which brakes will interchange so you can order them. Few parts dealers have a listing for the 1971 230.

First: Detect brand. Either ATE or Bendix. Then check with Pelican, this site's sponsors.