Disc Brake Master Cylinder With Drum Brakes?

I know crazy question. Here's the reason. I have the correct disc/drum master cylinder, proportioning valve and both lines to install on Vixen. What would be the result if I went ahead and did that but left the front drum brakes on for now, until I can afford the 14" tires and put my 14s on it? All this in the quest to keep her runnin and drivin, instead of putting her down until I can afford tires, which may be a while.