Since I've had the fuel pump out, I tested the two wires on both the new and old pumps. The reason for the major difference in reading is because I was send the wrong unit. They used the same part number, but sent out the unit for an Australian moto. They seem to use a different pump and sending unit, but in the same housing. The new one is the right size, but has the float pointing in the wrong direction to install right for the hoses to hook up. So that explains the huge difference in the readings from the 2 sending units. I found a universal gauge on Amazon that should be here today. I'm just going to mount it under the dash and call it good. The gauge was a little over $20, so a cheap fix, compared to replacing the stock unit. I was going to use the stock wires, but after looking at how big of a pain it is to get to them. I'll just run new wires. No big deal, wiring is kinda my thing. I've completely rewire several cars over the years, so this won't be that hard of a fix.