I'm using a 2004 crown vic brake peddle/booster/master cylinder in my '56 f100. The reservoir is wedge shaped because the master cylinder was at an angle in the car but is level in the truck. My question is what reservoir will interchange with this master so the top of the reservoir will sit lever?
No help for replacement, but I've been running same setup in my 63 with no problem just filled it full as i could
Not really a problem , it just looks like you have a low fluid level, which you do but not enough to cause bother.