I’ve heard some folks struggle with the factory fuel lines. I’ve never an issue with factory, quality repos, or decent factory style DIY fabricated flare-nut lines back in the day when the fuel lines were a non-serviceable part and could not be purchased from Chrysler parts, there were no reproductions then. In the seventies you could buy new carbs, manifolds, all hardware needed except the fuel lines over the dealer parts counter. Aftermarket fuel line options were far more limited than today.
I suspect most problems experienced could be avoided if a specific disassembly procedure is followed. Once initially assembled and tightened up, to disassemble, start with the flare-nut at the rear carb line to rear tee, use a 9/16” open ended wrench the stabilize the tee fitting, remove the rear carb, leave the flare-nut to bowl adaptor alone. Loosen the the rear tee to forward tee line, at the forward tee, remove center carb. Again, if there is no need, don’t mess with the bowl adaptor flare-nut fitting for carb removal. Next, remove fuel supply line to forward flare-nut, remove the front carb. Once more, this depends on the use of bolts rather than studs at the center and rear carbs as they need to shift rearward slightly to clear flare-nut fitting on disassembly.
Example of DIY lines fabricated from parts store fittings and straight lines using slightly some modified hand tools, circa 1976. This picture also shows the use of several other non-original easily obtainable, at that time, factory replacement parts. Note the call outs on the valve covers and cruise control.
