As long as the diameter of the supply line
is sufficient to get enough fuel
to the engine at full throttle, then it should be fine. If you haven't had any trouble with the engine acting like it was fuel
starved, I wouldn't worry about it. However, if the fuel
hose(s) are more than a few years old, I would replace them with some of the new ultra-low permeability hose. The standards have been updated recently, and the new stuff is much better.
The return line
should be the same diameter as the supply line
. The vent line
for the tank is usually a bit larger.