Brake portioning valve

I am in the middle of upgrading my D30 to disc brakes, am I going to need a new portioning valve set up for Disc front and Drum rear or will the original one work?

Also when I look at jeep4x4center.com they have
portioning valves:
http://www.jeep4x4center.com/product-information.asp?number=MBM-PV2
and "portioning valve upgrade kits"
http://www.jeep4x4center.com/product-information.asp?number=MBM-PV2K-2

Just the mount and the line stubs?

 

I got the adjustable one from Speedway, but I had to pull out the higher pressure residual valve in the rear and add a 2lb in line one works great.

 

Help! I need to know if I should let my original go!

 

I like the ability to the front to back with 4 wheel disc I would think that is more important with back drum

 

So I DO need a new one?

* edit: Just confirmed, I do need a new one.