Master Cylinder questions

[flyboy2610]

I have two master cylinders. They both have unequal reservoirs, which from my understanding indicates that they should both be for disc brake setups. The one attached to the power booster came from a '68 F350 that had power disc brakes. It has two outlet ports of very different sizes. The front port uses an adapter between the MC and the brake line fitting, whereas the brake line fitting itself screws directly into the rear port.
\The bottom MC came from my '68 F100 that had manual drum brakes all the way around. It has two outlet ports that are of close, but not quite equal, sizes. It uses adapters on both brake lines between the lines and the MC.
My questions are:
1: What exactly is the purpose of the brass adapter fittings between the brake lines and the MC?
2: I am going to use the booster in my '69 F250CS and install power disc brakes. I have brake lines for a '68 with drum brakes, that attach fine to the bottom MC. Can I use that one?
3: Did all drum brake MC's have equal reservoirs, while disc brake MC's have unequal ones? The manual drum setup that's on my '69 now has unequal reservoirs. Could I just use THAT MC for my disc brakes? I know I need a proportioning valve, and may go back to the salvage yard to get the one from the F350, unless some one has one they want to part with.
Thanks for reading this and helping me out.

[QC]

You cannot use drum brake m/cylinders for disc brakes. If you do the disc brakes won't release fully. The brass fitting in the 68 m/cylinder just adapted it to that vehicle. Ford used different sized fittings going in to the master cylinders so you couldn't hook them up wrong, I guess. Many of the castings are the same but the fitting sizes are different for different years or vehicles. A lot of new replacement m/cyls come with fittings to adapt them to different year trucks.

[flyboy2610]

Okay, I understand that part.
But why do they all have unequal reservoirs? I though drum MC's ha equal reservoirs.

[FORDification]

No, not always...I've seen as many uneven-reservoir drum-brake MCs as the even style.

Anyway, when it comes to something as important as the brakes, especially considering how inexpensive a new MC is, I'd just order a new one, correct for disc brakes. It would allow you a lot of peace of mind...know what I mean?

[flyboy2610]

Yea, I'm going to get a new MC. I was just confused about the reservoirs.
I get confoozed easily nowadays. Old age, ya know.