[Wootdog]

I have vacuum assisted drum brakes. I know for a fact that the regular drum brakes master cylinder is different than the vacuum assisted. Also the vacuum assisted is different than a disc/drum setup. The major difference I observed when I upgraded to vacuum assisted drums is that the reservoir is the same for fluid. i.e. same size. The disc/drum setup is larger in the front for the disc and smaller in the rear for the drums. I hope tht will help you some.
Kerry