I would avoid using the combined clutch and brake cylinder. they are expensive, and not as common as they once were.

Mechanical clutch linkage is almost always a better idea than hydraulic, less to go wrong and easier to fix on the side of the road.

But the major disadvantage to the combined master cylinder is you can't use a dual circuit brake master cylinder with a direct mounted booster.
The complete original system is not bad, but a newer dual circuit bake system is a much better idea.

If you use the original clutch and brake pedals under the floor you can easily use mechanical clutch linkage and mount a modern booster and dual circuit MC under there too. Makes for a clean firewall too.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-