BB A body pitman arm

That link has pitman arm K7074 (moog and others) EXCEPT 383 engine.

However, firm feel does list big block replacement idler and pitman arms
http://www.firmfeel.com/a_body_mopar_pitman_idler_arm.html

http://www.jimsautoparts.com/steering_parts.htm - Jims list big block also.

Mopar part number 3004809 (69 part cat W/383 engine)
Mopar part number 3004807 w/o big block



Read the Link supplied by SGBARRACUDA,,.

and here's a link for part #s

http://www.bigblockdart.com/techpages/moognumbers.shtml

hope it helps