Manual Brake System Trouble Shooting: Expected Line Pressure?

[BANKO]

Hey guys, I converted from a power booster w/ front disk and rear drum to manual brakes running Z06 6-piston fronts and still have the rear drums (for now).

Under panic braking I can't lock up the fronts and I feel a little scared at how much pedal input is required to slow down. Not sure if I have air in my MCs or if my proportioning valve is reducing the pressure.

Here is the setup I have:

Wilwood 6.25:1 pedals
Wilwood High Volume 3/4" bore (front)
Wilwood High Volume 7/8" bore (rear)
Wilwood adjustable proportioning valve

My balance bar is set equal front to rear and the proportioning valve is full open, with 57% reduction to the incoming line pressure. I think the pedal is too hard for being a 3/4" bore and have had others drivers give me the same feedback. Next action I'm going to take is to check the line pressure at the front calipers, does anyone know how much pressure is expected?