Any parts store will have high pressure fuel hose.
Cut a piece to length, and hose clampl it!
There are hose clamps that have rounded edges, which prevents them from cutting into the hose a little.
If you can find these, they should be used.
MANY of us 351w swap guys have done this... with no issues.
I used the stock Mustang fuel rails so I wouldn't have to relocate the regulator or mess with the connection location of the hardlines that come up the front of the motor.