Alright, update.
I decided to hook the pump up simply to see if it works. I have it in a 110v configuration as follows:
Terminal 1: Ground
Terminal 2: Neutral (White)
Terminal 3: 110v (Black)
Terminal 4: None
From doing some research and trial/error I gather that swapping the 110v hot from terminal 3 to 4 does absolutely nothing to switch the speed. Now, with the pump hooked up this way, it will run just fine until I get the system bled. At which point the motor gets hot in about 5-10 minutes and shuts off. This could be due to the pump being older, but I have my doubts in that theory because of 2 things.
First, I have two identical pumps/motors that were pulled out of the spa and they are both doing the same thing.
Second, I've heard running the wires from the breaker at a long distance as I have (abt 80ft with 10/3 Romex) could cause a less than stellar voltage drop.
Where I'm at now is trying to figure out how to run the pump/motor in a true 220v fashion to see if they run more efficiently. From the research I've done and looking at the diagram I think I need to remove the neutral and run the second 110v leg to that position as follows:
Terminal 1: Ground
Terminal 2: 110v (Red)
Terminal 3: 110v (Black)
Terminal 4: None
What say ye?