It's mentioned on Coolcats that you can swap on the Crown Vic master cylinder, the benefit being it's got a larger bore, thus more power for your brakes. Anyone know if it's worth doing without doing the 11" brake conversion too? I don't feel like doing that right now because my current rotors are only a few months old.
Well...actually the whole purpose of upgrading to the Crown Vic m/c is the greater fluid capacity that's needed for the rear disc conversion. That m/c is about 1/3 larger in capacity than the stock Cougar/T-Bird m/c. I think the bore is a hair bigger too. I'd be afraid that if you put one on a stock disc/drum configuration that you'd lose pedal pressure.
Unless you have swapped to the larger 73mm front calipers, there is no need to a larger capacity (or larger bore) master cylinder.
If you do, and keep the rear drums, the 1" bore MC from a Lincoln Mk6 works well. This may be the same thing as the CV one...not sure.