Brake booster issues...

The prices amazed me too. I put a booster/MC from a ~99 Breeze in my 65 Dart, using brackets and lever from a 73 Dart. Cheap at PickNPull. I just had to file the holes a little on the brackets. Many would work, but note that later MC's use bubble flares (see youtube to make). My MC has standard inverted flares.

I fixed the booster in my 65 Newport by cutting a new diaphragm from neoprene rubber sheet. Works in test, but haven't run much yet. That is a Midland-Ross with bolted clamp, so easy to disassemble.