So hydro clutch. I can find no example of it being installed in any 73-95 Chevy van from the factory. Everyone that ever posted a pic thank you for the help. With all the searching I did there are two things that convinced me of this, one was I saw they offered a cable around 90 up and the second was a guy in England on fake book that said his van used the cable. At that point I gave up looking for it. The parts sites will show you a master cylinder and the repair manuals will give an example how to bleed it.
I started with this, the lower is said to be from 78 and the upper is from my van.
I took it apart and slapped the clutch pedal on for some measuring.
I went to the store bought a cheap plastic miter box, plastic sheet and some grease pencils.
If you look up ticking stick, joggle stick, it is a old method of measuring and copying shapes. This can be useful for interior work where you want to find the shape-curves on the wall of your van.
You trace around the stick and get your points of interest.
Lay the pattern and stick down, line the stick to your marks and connect the dots.
I now have a drawing and start filling in the blanks. It only gives you a 2 dimensional point of view but it helps. I wanted the clutch rod to be straight with the cylinder at the end of travel for no side wear of the piston. I could find the length of the clutch rod and so forth.
Slightly better pic.
Slapped this together.
I ordered some 3x3 aluminum block and made a wedge to line up the master with the rod.
Drilled some holes.
Made it up to here so I could go outside and eyeball things.