Light duty brakes to f44 brakes

[Billgmcallen]

I have a 1991 gmc sierra k1500 non f44 truck. I am in the process of upgrading it to the f44 truck. Currently I am replacing the front hubs, rotors, and calipers with the f44 parts. For now I can only do the front, I don't have the money for a 14 bolt yet. But I am wondering if I should upgrade the master cylinder now and how that will effect the light duty rear brakes. I figure I'm not the only person doing all this so I'd really appreciate some advice.