I have one of these Valley 7450-20C pool tables as well. I am in the process of restoring it, and converting it to use a magnetic cue ball in place of the over-sized cue ball.
This has been a difficult task so far with no mechanical diagrams for the ball carriage mechanism. I'm currently working on the linkage between the coin chute and the lower carriage.
I am also converting the sub rails from a wood screw to a through bolt using a threaded insert in the sub rail. Most of the solid wood on this table turns out to be mahogany. So i'm trying to restore as much as I can.
I'll add a link to an imgur album of my progress thus far for anyone interested.
OP, if you see this, I found your rack holder plans on Thingiverse and used your model to make one out of wood. Thanks for that! Also, mine looks to be the same color as yours, a dark red/brown color. Minwax "red mahogany" stain seems to be a good match for color.
If anyone else has one of these Valley 7450-20C pool tables with any of the internal coin op mechanism in tact, I'd LOVE to see some photos. It would really help me in the restoration process.
Here is the patent for the ball return/carriage mechanism in the Valley 7450 pool table, U.S. patent #3115341 - "Pool Table with Ball-Releasing Means", filed Oct. 27, 1960. Nothing is to scale, but the mechanics are shown here. I have been using this as a guide for building the missing components. Hopefully this helps someone else as well. It took me a while to dig this up.
Also, here is an imgur album of the progress on my Valley 7450 coin-op restoration and magnetic cue conversion project.
There is lots more work to do...
Is there anyone with one of these pool tables which has a working coin-op mechanism?