Mine are approx twenty feet. They run from engine to a fuel manifold. Then from there to three separate tanks. I'm considering moving the manifold to the engine room. I don't know if this is kosher. Does the builder want it outside for safety reasons? I'm trying to shorten the lines as much as possible. I have had constant fuel pressure problems since I got this boat, I have added extra fuel pumps, changes filters etc, still have problems. But if there are other's running these kind of lengths, then I will try something else.

Particulars:

Separate 5/8 hose to each engine from manifold
Each tank has two separate 5/8 hoses with separate feeds going to manifold
Engines are 410 hp 502 carbed
Has carter type high performance pump mounted on engine. I have installed a extra pump in series. This gave me more pressure but it would not keep up under way.

My fuel manifold is on the bulkhead in front of the motor. The fuel lines come off the fuel pump and run up the stringer to the fuel manifold and then to the tank -- about 10 ft total length.