Thanks for the great info--but, I'm still a little unsure on what to do. It didn't occur to me that the under dash tee increased the hose size!?
Part of my problem is that I am adding tilt wheel to my brother's later model 67 and I am adding Speed Control to my early (built Dec 66) 67. I'm currently rebuilding the tilt columns on both cars, so I'm focused on this accessory but I'm factoring the Speed control project in as well, or, at least how it interacts with the tilt..
I'm also not looking to be absolutely concourse correct, but I want to be as close to some kind of restored factory correct as I can. I'm not worrying about colors on hoses or paint daubs, but the obvious things like correct vacuum cans/brackets/bolts, hose routing/size, proper Tees and check valves are very important. We do plan on driving these cars.
So, for my brother's mid year, factory A/C car, I would need a tee coming off of the manifold and a large hose leading to the outer nozzle (check valve) of the can, mounted under the battery tray. I then run a large vacuum line from the can directly to the tilt solenoid? It looks like it would use the same firewall hole as the AC line? I wouldn't need the 'increaser' Tee on his car. He also wouldn't need an in-line check valve because both the tilt canister and the A/C canister (smaller can in the wheel well) both have built-in check valves. Correct?
For my early year factory A/C and tilt, I keep the large can inside the fender apron and route the smaller line to the A/C as before--using the 'increaser' tee (which I have). I keep the single port in-line check valve that leads to the large vacuum can from the manifold. That is how the car was set up and shouldn't effect the Speed control. So, when adding SC, then I would add the tilt can under the battery tray as directed in the installation instructions. I run the large hose from an (added) tee from the manifold to the outer nozzle (the check one) and a large vacuum line directly to the SC control unit from the center nozzle (no check). At least, that is what I'm gathering from the installation instructions. Sounds correct?