Fuel Sending Unit | 3/8" or 5/16" Outlet | 1964-68 Ford Mustang

Restore accurate fuel-level readings on your 1964.5-1968 Ford Mustang with this direct-fit fuel sending unit. Designed to mount in the factory-style location inside the fuel tank, this sender is available with either a 5/16 inch or 3/8 inch fuel outlet and in stainless steel or zinc-plated steel construction, allowing you to select the configuration that best matches your Mustang’s fuel system and restoration goals.

Important: Choose the outlet size that matches the fuel line installed on the vehicle. A 5/16 inch outlet is commonly used with original standard fuel systems found on many early Mustangs, including six-cylinder and small-block applications. A 3/8 inch outlet is appropriate when the vehicle has a factory or upgraded 3/8 inch fuel line, including certain higher-performance or modified fuel systems. Model year and engine size alone may not confirm the correct size, so inspect the original sender or measure the outside diameter of the existing fuel line before ordering.

• 1964 1/2 to 1968 Mustang fitment: Designed for early Ford Mustang fuel tank sending unit applications.
  
  
• Two outlet sizes available: Choose a 5/16 inch or 3/8 inch outlet to match the vehicle’s existing tank-to-pump fuel line.
  
  
• 5/16 inch outlet option: Commonly used with original standard fuel systems on many six-cylinder, small-block, and stock carbureted Mustangs.
  
  
• 3/8 inch outlet option: Used with Mustangs equipped with a 3/8 inch fuel line, including certain higher-volume, performance, or previously upgraded fuel systems.
  
  
• Two construction options: Available in corrosion-resistant stainless steel or economical zinc-plated steel.
  
  
• Accurate gauge signal: Measures the amount of fuel in the tank and sends the corresponding signal to the dashboard fuel gauge.
  
  
• Direct-fit in-tank installation: Mounts in the factory-style sending unit location inside the fuel tank.
  
  
• Fuel-system restoration part: Ideal for fuel tank replacement, inaccurate gauge diagnosis, fuel-line service, sender replacement, or a complete Mustang restoration.
  
  
• Direct replacement use: Replaces a worn, corroded, inaccurate, leaking, damaged, or missing fuel sending unit.
  
  

This fuel sending unit is an important part of the fuel-level monitoring system on a 1964.5-1968 Mustang. A worn, corroded, damaged, or failing sender can cause inaccurate fuel readings, erratic gauge movement, fuel leakage, or uncertainty about the amount of fuel remaining in the tank.

Both outlet sizes perform the same fuel-level sensing function, but the outlet diameter must match the vehicle’s fuel supply line. The 5/16 inch version is generally the correct choice when retaining an original-style 5/16 inch line. This configuration is commonly found on standard early Mustang fuel systems and is often used on six-cylinder, small-block, and otherwise stock carbureted applications.

The 3/8 inch version should be selected when the Mustang has a matching 3/8 inch tank-to-pump fuel line. This may include certain factory configurations as well as cars that have been upgraded for increased fuel volume, performance carburetion, an electric fuel pump, or another modified fuel-system arrangement. Installing a larger sender outlet does not increase fuel-system capacity when the rest of the line remains 5/16 inch, so matching the existing line is normally preferable to using an adapter or reducer.

The stainless steel option provides improved resistance to corrosion and is a strong choice for long-term service, frequently driven vehicles, or restorations where durability is a priority. The zinc-plated steel option provides a more economical, factory-style replacement with a protective plated finish. Both versions are designed to restore proper fuel-gauge operation when installed in a compatible application.

Before ordering, inspect the existing sender or measure the outside diameter of the vehicle’s fuel line near the tank. Cars that have been modified over the years may no longer use the fuel-line size originally associated with their engine or production year.

Choose the 5/16 inch version for a Mustang retaining a matching original-style 5/16 inch fuel line, or select the 3/8 inch version for a vehicle equipped with a matching 3/8 inch fuel system. Then choose stainless steel for increased corrosion resistance or zinc-plated steel for an economical factory-style replacement.