the MC I'm using is a 7/8" bore tandem wilwood unit, marketed as being both for disc/disc and disc/drum setups.
I called wilwood today, and didn't get any definitive answers. The tech assures me that a 6.28:1 pedal ratio with a 7/8" bore MC should not have any issues generating the pressure required to actuate my calipers with authority. I bounced some ideas off of him, but we were talking it circles.
It appears I'm on my own to troubleshoot the system.
I re-read the directions on my mityvac 8500 pump today, and vacuum bled the brakes again. This time, I am 100% sure I have bled the system properly.
the pedal feels nice and consistent, but alas, I'm still not getting the stopping power I feel the car SHOULD have.
my next course of action is to replace the front pads (I'm hoping they're horribly glazed from sitting outside, or got contaminated from the ridiculous amounts of rust on the rotors) and that it will be the magic thing to cure my brake woes.
If this doesn't work, I'm going to get a brake pressure gauge and go from there.
If my pressure is low, I'm going to change the system from a single tandem MC to a dual MC setup.
if the pressure is ok, I'm going to upgrade the calipers with calipers that have a larger piston area.