Is your brake system manual, or boosted?
You won't need to change your proportion
Valve, but will have to set up the new system
on either one of those two criteria. 4 wheel
disc will require a master cylinder with a larger
bore diameter. (usually 1.032-1.125), and
running a 2lb residual check valve to the
rear if you run the newer style disc system.
(the pistons retract farther on the newer stuff).
Also, since you'll be introducing air into the
system, when bleeding the front calipers,
the bleeders have to be rotated to the highest
point.
I just went thru all this, but everything on my
brake system is new, using Ford rotors, twin
piston calipers on the front, and Ford Explorer
single piston calipers on the rear.
Note the residual check valves and
proportioning valves in the bottom pic.
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