Fuel Line Size?

I am currently running a stock 3/8 OD (.300th ID) fuel line for my stroker motor with a mechanical pump. I have never had an issue with fuel pressure.

I am converting to EFI. I will be using an intank fuel pump. The EFI system comes with 6AN connection fittings. I wanted to purchase some PTFE hose but the ID for 6AN is .312th. If I use standard 3/8 EFI hose the ID is .375. Should I stick with the .312th ID or upgrade to 8AN? How much HP will 6AN support?

more than you can think.

my friend has a 08 gt500 that makes 800rwhp on 5/16" stock fuel line.

I can only speak of my own experience. 493 stroker 3/8 fuel line Carter Mechanical pump...backed up by an electric fuel boost pump, on a separate switch only used for 1/4 mile runs..more than once I made TNT passes forgot about the boost pump..shifting at 6000 rpm and never had a problem running out of fuel to the motor..or a change of ET..

When I raced my 360 with 12/1 compression. I never had a problem with running out if fuel unless I forgot to turn on the electric pump If I forgot to turn it on. I would run out of gas around 800'. I loved the mechanical/electric combo. Never had a problem starting the engine. Just let the electric fill the carb and pump the gas and it started. That engine in my 2900 pound car ran 11.0's.
Now I have a street motor in it and it runs 12.0's with 3.23's in the back. A real street car weighing about 3300 lbs that I can drive to the strip, race and drive home. My 76 year old body is done racing. I need to sell the car before I meet my maker.

If you have any interest, I will send pictures with a detailed description

Stock style 3/8" OD steel line should be more than enough on the pressure side of the pump. That is what I run on my warm EFI 496 run on bothj track and X country. No issue. The stock style steel line also installs and packages well and safely.

I run a return style system with regulator in the engine compartment and 5/16 stock style fuel line as return. At the tank and engine ends, I use flare connection to pipe thread and AN racing flex hose.

The hard part is the suction side. If you have in tank pump, no issue. Run 3/8" steel line to the engine compartment with appropriate adapters at the ends. If you run an external high pressure pump that is tough. Most high pressure pumps do not like any suction or restriction on the intake side. External did not work well for me. An in tank pump is much better.

Check a Hellcat to see what the fuel line diameter is. I bet it is 3/8 or less. Pretty sure it isn't any larger than 3/8. The high pressure EFI stuff doesn't need big tube size.

Thanks everyone for the feedback. Andy great idea my friend owns one so I will have a look at it over the weekend.

I use a factory 3/8 supply line (-6) and a 1/2 inch (-8) return line for my 496 car. In tank pump. No fuel issues.