If the hose is to carry diesel fuel you should really replace it with hose to 'ISO 7840' standard this you can attatch to your engine and fuel lines or filter using stainless steel 'o'clips or better still hose clips of the correct size (avoid using clips where the worm drive is cut trough the banding as these can eat into the fuel pipe as you tighten them JCS hi-torqe are a good make)
you can make your fuel flexables as long as you like using the above standard so long as they are adaquatly supported.
if the fuel line is for petrol i am not sure what current regulations are i would check first.
I use a metal cutting disk on a grinder, just make sure you tape it first, stick a bit of rag in it to prevent dust entering the hose when you cut and put it in a vice or secure it to prevent movement and don't forget to put on your goggles when cutting.
Old Salt Oz.