so a couple of items.
I am shocked dr diff couldn't help, but let go through this again.

you have a 73 challenger that came factory with power drum brakes.
you swaped the drums for baer discs up front.
you do not have a factory proportioning valve, but a wilwood adjustible.
you have replaced the master cyclinder.

questions
did you replace the master with a factory drum master? or the disc?

do you know the size of the piston in the mc?

did you mess with the lines to the master during the swap?
rear port to front brakes and front port to rear?

did you replace the soft lines/hoses for the front and rear?

did you mess with the adjustible proprtioning valve once you changed to disc? as it sounds like it was on before your swap.