I posted this by mistake in the resto forum so I moved it over here for confirmation of what the responses were.

I did this years ago on a 66 B body but don't recall all the parts needed.
Refresh my memory?
Master cylinder
Tubing off the master to distribution block
Proportioning valve?? Do you need it on drum brake cars or only on disc/drums?

One response was "if you have drums just run the rear line direct to the old rear line. plug the port in the distribution block. leave front lines as they were."

Is this correct?

We run 70 C body master.Either for Drum Drum or drum disc.I run splitters but you could run a rear line to the master and plug whats there.No PP valve needed with drum drum.If manual make sure the little rubber is on the push rod.Rocky

67-70 drum/drum M/C. "Edelman" brass inverted flare fitting in the M/C port next to the firewall to adapt the M/C port to the OE large 1/4" line. Buy an appropriate length of 3/16" prefabbed brake line at your parts house & run it from the other closer to the radiator (forward) M/C port down to the splitter area & connect it to the line going to the rear (which you have unscrewed from the splitter) with a double female brass inverted flare "Edelman" fitting. Cap the now unused port in the splitter that the rear line was screwed into with an Edelman male inverted flare brass fitting. Call your parts house & see if they have an Edelman cabinet of fittings.

Thanks everyone.

I buy most of my brake line stuff from these guys:

http://www.fedhillusa.com/

I could urge you to use the correct fitting and re-flare the lines. All of those adapters don't look very tidy under the hood IMO.

If you don't use the brass safety valve why change to a dual master cylinder?