Originally Posted by Jbeas50
How much more will that cost cause I found an other rear end with the drums instead of the disk with 3.73 gears for 300 would I just be better off with that
No, you wouldn't be "better off" the disk brakes will improve your stopping power which is always a good thing.
I do not know what a proportioning valve and master cylinder would cost, but I doubt it would be very expensive. Google search for some fitting a 93 Cobra, they should work for your purposes.