Yes another MC question. I've read on the MANY different ways.
I'm staying with the drums all around.
1967's had drum x drum with a dual pot.
I have a 1967 NOS dual pot. Part #D2UZ-2140-A
Is this a simple plug and play? Do I need to extend (or get a longer) pushrod?
When MC is installed I have about 1/2" of back play on the pedal.
Is Illustration #2B257 needed?

 

Who told you this is a 1967 master cylinder? It's not, nor is it for any F100/350.

D2UZ-2140-A = 1971/72 E100/300 (Econoline) with power drum brakes. Parts catalog sez use with D2UZ-2005-A P/B booster & D2UZ-2031-A mounting bracket.

2B257: Brake Pressure Differential Valves introduced in 1967 along with dual master cylinders.

But, it's a good idea to stay away from 1967 parts (master cylinders, boosters, valves) because they were only used in 1967!

 

The illustration shows MC as #2140 also.?