Can anyone explain how Holleys efi Fuel Tank Module 12-305, can work with efi without a return line?

 

The 12-305 is nothing more than a typical in-tank pump having the added feature of a pressure relief valve built-in.

 

Why doesn't anyone else use a system like this (OEM) instead of 2 lines? Would I be better off with a conventional setup?

 

At a certain point, Ford went to returnless EFI systems on ALL their engines, just not all the same year. For example, The Explorers had an early returnless system for several years which proved not very acceptable. The redesigned system was far better. It uses a means of controlling the PUMP SPEED to maintain constant fuel pressure. This means pumps last much longer, trouble-free. My 2004 has 184,000 miles on the original pump, still running nice and quiet.

 

I have a 65 with a 427 small block 750 carb, stock tank. Thinking of switching to





I have a 65 with a 427 small block. Thinking of switching to EFI. I can use the stock tank and use Holleys single line pump or Spectra Premium SP169A1H pump with two lines. Which would you suggest?

 

Both methods have good and bad points. Single line system allows engine to use just the amount of fuel it wants, while the pump keeps working like hell, thus shorter pump life. Single line side-steps the hassle of adding a return line to the tank. Fuel remains cooler, in the tank.

Two-line system circulates fuel to and from engine whenever engine is running, thereby increasing fuel temperature in lines adjacent to the hot engine. This means the fuel temperature in the tank is higher than it would be with no return line. Also, pump life is shorter.

 

How can they both have shorter pump life?

 

Sorry. There are TWO common single-line fuel systems. I assumed you wanted to know specifically about the one offered by Holley, which DOES have shorter pump life in general than the Ford system which continually controls PUMP SPEED based on engine demand. Pump speed control extends pump life since it allows the pump to run slowly when power demand is low.