PJDEE,
I'm trying to remember how my '54 3/4 ton is set-up...
I'm pretty sure there's just one line coming-off the MC (hole is set-up with a 1/4" female inverse flare), which runs across the crossmember under the bellhousing, to the right-hand frame rail.
There it meets a brass block with three female 1/4" tappings: one line goes to the front wheels ('nother block at the RF wheel, line crosses back at the front x-member to the LF); the other line runs back the right frame rail to the flex hose at the rear axle...
( This is definitely how my '55 first 1.5 ton is plumbed...)
If you have a deal with a junction block held to the MC by a fluid bolt, that might be a challenge...try going to a place that services big trucks and see of they match-up your fitting...Willys used a "Y"-type block on their master cylinders...
Good luck...