Dual Feed Fuel Line Setup

I believe the 5/8 18 might be for a demon/ barry grant carb, or maybe a carter/edelbrock. The older holleys used 7/8x20 for the fittings into the bowl, but then depending on which adapter bowl fitting you use determines the hard line size you need. I don't know for sure what the new holleys are using.
On mine i use a pressure regulator on the passenger inner fender, with a gauge, two braided teflon lines (alcohol in the pump gas) to dash 6 an fittings into the carb. With all an fittings you're right, it is NOT cheap.
If i was just trying to hook up a holley to a mechanical pump, i dont know what i would do. I cant find anything of quality that i dont think is overpriced, and even the garbage chinese stuff is too much money imo.