Bill, you don't say what size/design brakes you have (other than that they are Mustang/Mustang Cobra factory pieces), but if my experience can be of any help, here it is.
My calipers are Wilwood Dynalites...4 pistons per caliper. The rotors are 3/8" thick, not ventilated. I had a Ford style master cylinder on it and it was leaking into the cockpit, so it had to go. I posted a thread and the issue that confounded me was the pedal ratio (my replica has a home-made pedal box and the pivot point is up too far to be able to get a good measurement.
With all that was going on, it was obvious that I had to take a shot in the dark. I had not been happy with the pedal feel even before the MC started leaking...l really wanted to use the Wilwood power brake system, but like you there was not adequate room between the firewall the the fenderwell, so power brakes were out of the question.
In the end I switched from a Ford style master cylinder, which has one large reservoir and one small reservoir, to a Corvette style master cylinder, which has equal size reservoirs for the front and rear systems. My "leaky" master cylinder had a 1 1/16" piston size, so I dropped down by 1/8" to a 15/16" piston in an effort to get more stopping power with less pressure on the pedal.
I am very satisfied with my choice, the brakes are rock solid and there is no fade. Since the front and rear calipers are identical, the choice to switch to a 'Vette style master cylinder was the correct choice.
I had to approach it in a trial and error manner, I just got lucky with the first trial. I notice you'll be using remote reservoirs...that thread Mr. Bruce posted shows a very small master cylinder with the fitting for the hose to the remote reservoir...looks very small to me. If you get to choose from a variety of piston sizes, I found out that the smaller the piston size the less pedal pressure is required to get the same stopping power.
Of course, if your brakes use larger pistons than my Wilwoods, or more pistons per caliper, you may need a larger size piston.
Good luck...I've been watching your build thread and this is going to be one incredible car when you're done.
Cheers!
Dugly
Threaded Mode
