Fuel fittings

Ok the inlet on the chrome fuel line feeding both the fuel bowls on my Holley has a 5/8-18 thread. Is that a plain old SAE fitting or NPT?

Next on the fuel pump fitting (Stock replacement pump) Was told it was a 1/4 npt. 1/4 " fuel line from NAPA is too small, 9/16 a hair too big. 1/2" I guess? Not NPT?

For your future use ... PIPE or HOSE is measured on the I.D. and TUBING is measured on the O.D.

5/8-18 is a standard fine thread tap size or possibly an AN size or INVERTED FLARE size..

I went back to NAPA with the chrome fuel line for the
carb. You can see in the specs it lists a 5/8-18 fitting for the inlet.

http://www.summitracing.com/parts/HLY-34-160/

The
guy gets a 3/8 SAE flare fitting steel brake/fuel line and it threads in and
he says thats what I need. I tell him the specs for the fitting are
5/8-18. I tell him its inverted flare. He says I will have a hard time finding that and this will work.

Im REALLY confused now.

I stopped at Lowes and
got a 1/4" NPT fitting. It is too big for the fuel pump fitting. What
size is it then?

Does anybody know what size the internally threaded fitting on a stock replacement fuel pump is?

All I want to do is run a hard line between the chrome line and the fuel pump and have a fuel filter somewhere in between. Or hard line at each end with fuel hose in between with a barbed fuel filter. I thought this would be easy.

5/8-18 is the thread size for the B-nut... -6 tubing, -6 means 6/16, or 3/8 flare - that should work.

I would think the stock pump would have a 1/4NPT outlet, but I have never dealt with a stocker. You're saying 1/4NPT is too big, so you're going to have to step up/down at either end to make it work. Is it a pipe thread right into the aluminum, or is there a brass adaptor there? A pic might help...

Stock fuel pump. usually 1/2-20 inverted flare