There's also a place in downtown Sacramento, Ca. called "power brake booster company" or some such name and they have all the parts you'll need. They're very knowledgeable of Mopar brake boosters.
cudajim Your close on the company's name. Power Brake Sales, is the official name of the company. Delt with them in the past, when i was a wrenching mechanic, in mid town Sacramento. Good people to do business with. A link to their site, above.