AdamK1500,
" . . . my head is spinning trying to figure it out with out the VIN"
What is your "VIN" - from the ID plate?
What is your registration ID/"code"?
I have a 1954 GMC 350 COE - it has a 1.5-year-only (Z-series GMC) vacuum-actuated 2-speed-rear switch. It is attached to the front of the dash to the left of the steering wheel.
This shows the hole in the 1954 dash for the 2-way-rear vacuum-operated/actuated switch Here is a close-up photo of the switch Selector switch What attaches to:
- left line (to 2-speed diaphragm at rear end)
- rear line (vacuum line in through the firewall)
- needle line (line to speedometer 2-speed-adapter)
2-speed-selector on the rear of the speedometer 
