I've had the same copper 3/8th fuel line from my fuel pump output to the 390 Holley inlet, for better than 25 years on my 292. Still no problem. [It's connected w/ 3/8 rubber fuel hose 3" from fuel pump and goes into more rubber fuel hose and a G15 gas filter before the carb. -- that probably negates vibrations]
I'll let you know when it fails me.
In fact, the rubber hoses and fuel filter I just replaced today (about every 2 years or 10,000 miles.)
