The pumps you're looking at are the same, they are called "Saginaw P pumps" also used on some IH trucks.
You'll need for find a PS pump pulley, and also find out what it's used for so the setup can be duplicated.

You should be able to use a lot of 3/16" material, but may need some 1/4" depending on design.

I like your idea to drive the PS pump, then piggy back the alternator, shouldn't have problems with the belt slipping.

IF you don't have room for the PS reservoir then you could use one with a remote reservoir, http://rides.webshots.com/photo/1484223987080251109mvGaMx

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-