I have a 1988 F-150 with a few mods that have greatly improved the power level. I added a 255lph external pump to give a better fuel supply. My truck has the non-electrical selector cannister mounted to the frame, a low pressure pump in each tank and a high pressure external pump. I wanted to add a high volume, low pressure pump to the tank to assure a good fuel supply but have had a hard time finding one as almost all of the high volume in-tank pumps are also high pressure. I found out putting a high pressure pump in the tank will result in major fuel leakage out of the selector cannister so I definitely need to get a low pressure in-tank pump.

Is there one available ? If so, where can I get one ? Thanks for the help.

 

You don't need one, even if it existed. If that crappy old fuel system won't support your engine (which I doubt), the best thing to do is swap to the '90-96 system. It's easy & relatively cheap if you use JY parts.

 

I have definitely thought about that. I already have the high pressure in tank pumps and have an external pump as well. If the current system won't support the power, I will probably make a system replacement. In the meantime, I will also see if someone has a pump available for the job...

 

After thinking about this, I am not so sure an upgrade to the modern FDM will do the job. It appears this is an assembly that does not allow the fuel pump to be replaced (At least I couldn't disassemble the FDM on the truck I pulled one from). So the stock pump on the FDM is liable to be a low volume unit which is the problem I have with the current internal pump. So I end up needing more fuel flow for the power level and it appears I only have three options. One is to find the high flow, low pressure internal pump or use a high flow high pressure internal tank and regulate the pressure down before it reaches the selector cannister which is liable to be a nightmare to implement. The final method may be to add another external pump similar to an external Holley carb pump that can suck the fuel from the tanks also. So that would mean I operate 3 pumps at once...

 

No, if you swap to the '90-96 system, there is no external canister. The lines from the tanks to the fuel rail are basically straight, and hi pressure the whole way. It's a much better, simpler system. If you get the FDMs & fuel lines, it will replace all your fuel lines, the DFR, the external pump, and the filter - the whole thing. You MIGHT need the newer tanks if yours have small sender holes. Read these captions: