I question the wisdom of running a Ø1.125" bore master cylinder with those two Wilwood kits, as they're designed to operated at higher pressures than the factory Ford or GM type disc brakes commonly found on EB's. Generally speaking, the best/easiest way to increase operating pressures is to decrease the MC bore size or increase the booster size. Given our space limitations under the hood, short of going hydroboost, you can only go so big with vacuum type power brake boosters, with a dual-9" being about the largest I've seen fit on an angled type bracket.
The 140-13303-* Wilwood front kit uses a compact Dynapro 6-piston caliper with 5.06 sq inches of effective piston area, a full 23% less than the factory Ford single-piston calipers with Ø2.88 piston diameters, and ~25% less than the GM D52 calipers with Ø2.94" pistons. To generate the same brake torque as either the Ford or GM factory kits, you would need to supply an additional 23-25% pressure to the calipers. You can do this by pushing harder on the pedal, or reducing the MC bore size...I know what I'd do. If you were to run a Ø1" bore MC, that's about a 23% difference in MC piston area, so that seems like a logical choice.
Just an aside, but the front rotor is Ø11.75" diameter, so virtually the same as the factory Ford rotors which measure Ø11.72". While the diameters are similar, the Ford rotors are ~1.18" thick versus .81" for the Wilwood rotors, a full .37" thinner than the OE rotors. The thermal mass of the OE rotors is significantly greater, which provides more thermal capacity and therefore better resistance to fading, lower average operating temperatures, etc. While this doesn't impact effective brake torque (not until the brakes fade anyway), it is a significant step in the wrong direction if your goal was to have higher performance brakes overall. That said, the rear discs should help, but they're only doing about 20-30% of the work on an EB depending on your rig.
Tobin
