If you are building a concourse GN for car shows it is a 5/16" fuel line hose. If it is a typical street/strip car and not trying to be 100% original, cap the hose spuds off on the water tubes. Not needed. I remove and weld the spuds closed on most cars. You can take a torch and melt the solder and pull the spuds out of the tubes, and then take a 1/8" pipe tap and thread it for pipe plugs. A little sealant on the threads and BINGO, no more ugly leaking hoses. Not sure if there is any REAL gain in removing the hoses, but they are surely not needed.
