So I’ve been looking at these fuel pump to carb steel lines for my 390 (w/Holley C7OF). I just have a rubber fuel line running there now. I’d like to replace it with a steel line, but I don’t understand how they connect at each end. My Carter fuel pump and the fuel filter attached to the carb have hose barbs and the steel lines all appear to have brake-line like fittings on them. Can anyone explain to me what I am missing here?
I don’t know what your situation is but my fuel pump had a threaded fitting with a steel line that had been cut so a rubber line could be run to the carb. The line from the fender to the pump should connect to a hose barb on the pump. I just had to unscrew the improvised barb and attach the threaded steel line. Just be aware that the steel line will need to be adjusted. I had to massage a couple of the bends to get it to terminate at the carburetor fuel filter connection.
Ok…I’ll look at the fuel pump fitting a little closer. What about the carb end though? How does the line fit to the filter/carb?
A stubby section of rubber hose connects the barb on the filter to the barb on the end of the steel line
Thanks so much. I appreciate your help!
The fitting on the hard line at the pump threads into a brass fitting. Sounds like you have the wrong type of fitting there. It should be pipe thread where it goes into the pump. The fuel line is 5/16" reverse flare. Here’s a photo of an original pump for reference:
You can get a replacement fitting at home improvement / hardware stores, auto part stores, eBay, Amazon etc. WCCC also sells them as well as any of the Mustang / Cougar part suppliers.
What Royce said, the fuel line from pump is 5/16 and my holly is a 3/8. When I swapped the new holly I just went to the (insert your local name ) harware store and bought brass fittings with new rubber hoses. After getting nudged for awhile from my friends about rubber hoses and after I read gyrhead’s fire incident I went metal tubing all the way. I didn’t trust myself doing flares so I just cut the flare end off and went compression fitting 5/16 to 3/8 and bent the tubing to how I wanted it to lay in the engine bay. 
Or you could simply buy the correct fitting:
Some aftermarket fuel pumps use a 1/8" pipe thread so you would then need one of these:
Forgot to mention they also sell them at Farm + Fleet, Tractor Supply, Menards, and many other retailers across the world.
I guess the concern here is that the rubber fuel like can crack and leak (like mine did last week).
Thankfully I smelled it and pulled over and fixed before any major problem. I’m wondering if you go with metal all the way how to incorporate filter. Do they make those other compression fittings as well?
Many thanks to everyone here. I truly appreciate the help and advice with such a basic issue.
Thank you very much for the links Royce.