I had the opaque nylon fuel line on the car until a couple of weeks ago. Good stuff but it has one problem in that it sometimes isn’t flexible enough and it takes a firm “set”. I also had the VERY expensive ($80) “T” piece that connected from the line to the carbs. After a while the line, now somewhat more rigid, stressed the connection from line to the “T” piece, to the point of failure. I now have the rubber fuel line installed with a new brass “T”.