Proportioning valve?

I am replacing the original master cylinder with a newer unit. If I am keeping the original drum brakes, do I need a proportioning valve?

 

This may be helpfull

I plan on disc up front with rear drums, cylinder located under floor.
This link has some information upgrading from the original.
Check out all of the tabs.

http://mbmbrakeboosters.com/index.ph...id=8&Itemid=16

 

Thanks for the information.