Best type for accurate readings will be this type
http://www.jamestowndistributors.com...l+Sending+Unit
Moeller Electric Type Fuel Sending Units are Reed switch sending units that collect fuel level information by taking the measurement from the float.
These Reed switch sending units are designed for gasoline applications only. They are calibrated to 33-240 Ohms, and feature durable, 316 stainless steel construction to withstand abusive marine environments. A Direct Original Equipment Manufactured sender replacement by WEMA USA.