I think you may be able to find something in a truck wrecking yard.. I mean class 8 trucks that is, semi and 10 wheeler type, I think some of them had 5" from the breathers to the engines. Mostly aluminum tubes and rubber elbows but that may work if you can fab it a little.. Just make sure to have a long enough section of rubber to allow for the engine rocking or it will rock the breather on top of the carb ..