old brakes, need upgrade

[LPoole]

I have a 68 c10 with old brake set up. drum/drum, no booster. im wanting to upgrade the brakes... disc/drum w/booster. my question is this... what do I look for in a MC/booster set up for drum/drum brakes ? I see a lot of setups with proportioning valves for disc/drum or disc/disc set ups. do I use one of these set ups and not use the proportioning valve ? I just don't have the cash for the front disc conversion right now and was wondering if I could go ahead and get the MC/booster put on to help with braking until I do have the money for the full conversion. thx ahead of time for any info.