72 Duster master cylinder

[ev2duster]

I need to replace the master cylinder on my 72 Duster. The car has manual drum/drum. The old cylinder has a larger reservoir in the back, closest to the firewall. The replacement has equal size reservoirs. I've been told that the replacement is the correct one for the car and that the old one is for a disc/drum vehicle.

So my questions are..

* have I been given the correct info so far?
* is there a difference in the length of the rod that comes out of the back of the cylinder?

I really hope to get this done asap, it's going to be way too nice this weekend to have the car just sitting.

Thanks!