Kurt,
Thanks for the photos of the dual action pump plumbing. Years ago (10), I put a "new" JC dual-action pump on my Suburban. I did not know how to route the plumbing and all I had was the Factory Assembly Manual. It does not have a good illustration for a 3100, so I tried one of the larger truck routing. The tube bending was too complex for my limited bending skills/experience - it looked awful. I soon took that pump off because it was defective.
I have a new Chevs of the 40s pump and will mount it on the 54 3104 that I am restoring, and I will use you much more logical routing. Your routing is like what Denny Graham used.
Thanks, again,