What dual master cylinder will work on a 1965 Chevelle with all drum brakes.

Search this section for my 'jury pool 2' thread, and scroll down to the links for master cylinders...there is at least one good one. All you really need to do is match your bore with an appropriate replacement, and hope you don't have to change fittings. Best I can do for you. I just noticed no one else replied.

Good luck.