The two sources that I know of for 10AC alternators are Sunbeam Specialities, $223.00 (new), $115.00 (rebuilt with exchange) and Victioria British, $140.00 (rebuilt?, no exchange required, w/o fan or pulley). Another idea if you don't need a _new_ unit is to have it rebuilt locally. I had mine rebuilt for about $65.00 at a local shop a couple of years ago.
Brake servo and brake master cylinder rebuild kits are available from both sources mentioned above.
Call Smitty (at) (619) 233-7937 for engine availability here in San Diego.
Terry Edlund B395009965 San Diego, CA