Now, what would be an ideal matching setup? RIght now i want to run the larger Mach 1 calipers but i don't want to run into issues with the pedal being softer than if i ran the 94-98 Cobra calipers?? I have both, so it's just a matter or selecting which to use.
Or, should i ditch my current MC and go with a 93 Cobra MC with either of the two calipers?
It all has to do with calculating hydraulic ratios and then plugging in differnt components into the calculations to see how they stack up.
First off, let's get some numbers:
Early PBR Cobra Calipers have two 38mm pistons, giving a total area of 238.8mm^2 (area - pi * diameter). Later PBR Cobra calipers have 40mm pistons, giving a total area of 251.3mm^2. (For comparison, the old SVO calipers had a single 73mm piston with 229.3mm^2).
The 15/16" master cylinder has an area of 74.8mm^2 and the larger 1" master cylinder has 79.8mm^2. The big-daddy is the SVO master cylinder with 89.8mm^2.
When Ford first introduced the PBR Cobra caliper in the '93 Cobra R, it had a 1" bore, giving it a hydraulic ratio of 3.0:1 (caliper area divided by master cylinder ares.) Folks complained about the stiff pedal, so when the '94 Cobra came out, Ford fitted a smaller 15/16" master cylinder, giving it a more conservative 3.2:1 ratio, resulting in a longer, softer pedal.
I SUSPECT (because I can't remember!) that the later Cobras with the 40mm calipers used a 1" bore master cylinder, giving it a firm-ish 3.1:1 ratio. Putting in a 15/16" MC would have given it a less-form 3.4:1 ratio -- still not bad, though.
So if it were me, I'd just mix and match the caliper and master cylinder and try to keep the ratio around 3.2:1 or so. A smaller ratio means a shorter, firmer pedal. A bigger ratio means a longer, lighter pedal.
(Case in point -- for a very short time, I drove my car with early Cobra PBR brakes and an SVO master cylinder, giving me a stupid-hard pedal -- the ratio was 2.7:1.)