[rotorwrench]

I've had several jury rigged old cars and motorcycles that ended up with rubber line adapted in for filters, different carburetors, etc. On the motorcycles, it's pretty much OEM to have rubber line but I've had leakers on more than one occasion and was just lucky that the drafty old turds would let enough vapor into the cab or fuel on my pant leg to get my noses attention before catching fire.

I could safely say that copper will most likely outlast the flimsy rubber hose. This still puts in into one of those "maybe it wil last" catagories. If the copper is mounted from one point to another on a solid foundation like between a carb and pump, it will last longer than a mounting that attaches from one point to another in a flexible situation like between an engine and a firewall where the engine can move separately from the body. The flexibility will cause fatigue at a compounded rate over a more stable mounting.

You can throw caution to the wind and take your chances. Some people like to take chances. I hope your Karma is good. Keep in mind that your passengers don't have a choice in the matter.

On the aircraft engines, I still anneal the copper spark plug washers at every 100-hour inspection to make sure they seal better at each torque up after testing.