My 8 stack EFI build

[my427cobra]

Hi all. As I continue to make progress on my 8 stack EFI build, I've come upon a rather curious situation.

I am using an FiTech fuel delivery system: inline fuel pump and filters.

I am mystified by the mismatching of AN fitting sizes on the FiTech system.

Starting at my tank: it has a -8AN fitting coming out of the sump (my dual 4bbl carb setup was plumbed with -8An fittings and 1/2" SS braided hose from the tank all the way to the fuel pressure regulator in the engine compartment)

Now the first component in the FiTech fuel delivery system is the "pre-filter" which has -6AN male fittings on the inlet and the outlet.

Then the in-line electric fuel pump (225LPH) has a -8AN inlet fitting and a -6AN outlet fitting. These fittings have metric threads going into the fuel pump.

Then the in-line filter has -8AN male fittings on the inlet and outlet.

So starting at the gas tank it would be a -8AN (tank outlet) going into a -6AN coming out a -6AN (pre-fiter) going into a -8AN coming out a -6AN (fuel pump) going into a -8AN and coming out a -8AN (in-line filter).

What's that all about?

I'll be changing them all to -8AN fittings.

Any thoughts on this?

The -8AN line would then run to the engine compartment to connect to the fuel pressure monitor block and the up to -6AN fittings on the fuel rails then out of the fuel rails to the fuel pressure regulator and the -6 return line to the tank

Cheers
Greg

[ERA 626]

I have a cross ram. Similar to an 8 stack , it has 8 individual runners. I am using a megasquirt ECU. My entire system is plumbed with -6an fittings from the in tank fuel pump all the way to the fuel rails... no issues. I maintain 50psi fuel pressure, a 650 HP motor.
photos in my build thread. in CSX 6079 build.
CSX 6079 build

[map]

https://www.youtube.com/watch?v=uDCz...ZUEQed&index=1



https://www.youtube.com/watch?v=uDCz..._gB_L9h4ZUEQed

[Snake2998]

I'm not clear whether you have a swirl pot or not but in my experience inline pumps hate sucking and lose performance if at all restricted on the suction side . So the biggest suction line you can fit together with the shortest suction line possible is a very good thing.

[my427cobra]

Thanks guys for all the good info and advice.

Cheers
Greg