Hello. There is no visual difference between the 0-90 ohm and the 0-30 ohm sending units...the difference is the resistor assembly is calibrated for 0 ohm empty to 90 ohms full. The pick up tube and float arm assembly are exactly the same since I use the same parts that are supplied to the other parts vendors - only I assemble the sending unit with a 90 ohm resistor. Let me know if that makes sense. You're welcome to email me at: vincent@mayedamotorsports.com
