I am having a small problem rewiring my 1985 Jeep CJ7. I am putting in a set of aftermarket gauges and the fuel sender unit that is supplied is going to be a bear to install it. On the Jeep, my fuel pickup tube goes through the same part as the oem sending unit does. The aftermarket sender does not have this capability. So...I was planning on using the OEM sending unit with the aftermarket guage. When I hook everything up, the aftermarket gauge reads full with the sender in full and 3/4 full with the sender in empty. The guage is a 240-33 ohm. From what I can figure out, the sender reads from 73-10.

How can I get this to work? A resistor somewhere?
Thanks
Mike