Sure sounds like Pedal ratio. I just went thru this too. Hard pedal & no way I could lock up anything.

Read through this....

http://www.hotrodheaven.com/tech/brakes/brakes6.htm

Mine is a c-body & there's 2 different pedals for the Power & manual setups. Also 2 different hinge points for each Pedal.

Doc diff sent me that link & sure enough my Pedal ratio was 3:1 & I needed 6:1. Modified the pedal & it's much better now. Working on other issues with the Brakes right now.

Butch