yes and no
ideally you would want to do a 3 to 2 port conversion, gut the stock proportioning valve so that it becomes a distribution block. Then install an adjustable proportioning valve in the rear brake line.
At that point you can play with master cylinder sizing to suit your needs. I have a SN95 V8 (non cobra) M/C on mine and I personally think that the pedal is a little hard. I may try a 15/16 (24mm) M/C from a Cobra and see if that helps. I bet it will.
lastly if you are using the stock K member you might outta think about putting 94-95 spindles on. The steering arm is a little lower on the spindle in comparison to the 96+ spindles. With 96+ spindles, the arm is higher, and makes getting bump steer adjusted properly a little more challenging--you will have a good size stack of spacers.
on the rear brakes. You will definitely want to install the disc brakes that match your front brakes. Leaving the rear stock (drums) will mess with the brake bias.
it's best to do it all, once, if possible--and do it correctly. Brakes and steering are not items that you want to skimp on!