i am in the process of converting to disc brakes on the front of my 69 . Do I need to change the proportioning valve too? It has power drums on it now. I have a proportioning valve from a 72 Monte and its completely different. Can anyone shed some light on this subject for me? Thanks!!!

Yes, you need to change to a disk/drum prop valve. The Monte one should work fine, but you will need some fitting adapters to use your existing lines.
Bill C.