In case this helps someone else, the correct size hose is 12mm. The original hose is a cloth braid covered hose. Best I can tell, it is still made by Continental in Germany. Sells for about $9 a foot here in the US. I opted to use US hose as Steve confirmed. There are only 2 sizes of true vacuum booster hose sold in the US - 11/32 and 15/32. NAPA and O'Reilly both sell the correct 15/32" and both carry Gates Rubber. From my research, the Gates hose is spec'd for up to 30 in. HG of vacuum. Sells for less than $4 a foot. You need on the order of 5 feet and cut to fit. Another delightful one-man job feeding the hose from top of the motor and then crawlng under the car to connect the other end.
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