'65 power brake single to dual conversion

[ncoonen]

Okay, this data is probably somewhere in plain sight but I couldn't find it. I have a '65 C30 with factory vacuum power brakes and the original single circuit master cylinder. I would like to convert it to a dual circuit system but retain the factory booster and four-wheel drum brakes. Most questions like this involve front or four-wheel disc brakes. I am sticking to drums.

Is there an off-the-shelf all-drum master that will bolt up to the original booster? If not, what booster/master combo do I need to keep the drums?

Thanks...ned.