Safe to plug a fuel line? (Ford Truck)

I have a 1990 Ford F150, 4WD, 5.0L V8, with 2 fuel tanks. Each tank has an in-tank, high-pressure fuel pump, with no secondary pump in the system. The check valve in the front fuel-tank pump is broken, causing loss of fuel pressure and difficulty starting. I have verified this by dropping the front tank and plugging the front-tank fuel lines with basic rubber plugs, and the truck starts and runs fine with just the rear tank opperating. My question is: Is there a safe way to permanently plug these lines so the truck is drivable? I use this truck just for utility purposes (less than 2000 miles/ year), and I would rather not spend the money and effort to replace the front-tank fuel pump. If there is a way to safely plug the lines, how would I do it? Any help would be greatly appreciated.

The tricky part of this is the fuel system is integrated, meaning it pulls gas from either both tanks or one tank at a time. Safety isn’t an issue as long as you are sure no gas is spilling or leaking.

Diaable the fuel pump in the tank you want to put out of service. You can cut the wires, or pull a fuse whichever is easiest and isolates that fuel pump. Then you can cut and plug or crimp the fuel lines. Be sure no air can enter the operating fuel system.

Don’t expect your gas guage to work properly and give accurate readings. You will need to zero out your trip meter to determine how many miles you’ve driven and buy gas accordingly.

Perhaps it would be easier to price out a replacement fuel pump.