I ran the top connection on my expansion tank to the small connection on the front "Y" Pipe off of the thermostat housing.
The lower expansion tank connection went up to my small connection on the radiator, where-ever it was..... I believe it was at the bottom....
My diagram I posted showed originally the lower connection on the expansion tank tied into the crazy hoses that were the heater shut-off valve circuits. I believe you said that you weren't running a heater???
For testing just connect the main large connections and don't worry about the small stuff. Connect it like it was in a regular Ford! Keep the radiator high enuf to be the "top tank" in a normal car, and just watch the water via the radiator cap there! Keep it simple!!!!
Make some noise!!!!!