2litre conversion ?upgrade fuel lines?

hi there, im doing a 2litre block mk2 golf head  running on carbs, i have got the 130 chassis im doin it in to and have moved the engine mount etc, i have the small is it 8mm?? fuel line, i have some bigger copper pipe i was thinking of running all the way from the tank inside the car to the front inside the car is it worth it? or will the old lines b ok?
p.s im track daying it and its all stripd out so the fuel lines will be all clipd down inside if i do it this way.

advice appreciated

simon

I would say, yes - Change them.