Am I expecting too much?

[67gtonut]

67 GTO manual brakes

Stock style Single piston calipers up front
Stock rear drums
Wilwood 7/8" tandem master
Adjustable prop valve



Should I be able to lock up the wheels under heaving braking?

Just installed the Wilwood master.... bled the crap out of it... took a bit, some air was trapped in the master. I have a decent pedal, little mushy, but not bad. I cant get front or rear brakes to lock...... Really never could.....

Am I heading for at least a small 7 or 8" booster to get enough clamping force to lock wheels? OR am I missing something in this manual set-up?

Thanks

Troy