MG Car Repair: 1975 mgb Distributor vacum advance, vacuum advance, manifold vacuum

Question
recently put together a 1975 mgb. ended up with an extra hose. is there a vacuum hose that goes from the Carib to the distributor and if so where do they connect?

Answer
Hi Mike,
According to the manual, the 75 MGB had a vacuum advance unit fitted but it was not connected. They depended completely on the initial advance setting and the centrifugal advance.

I don't remember it that way but the Bentley service manual clearly states that.

A rule of thumb I always used was that if a distributor had a vacuum advance unit it used ported vacuum (vacuum that only activated off of idle) and if a distributor had a vacuum retard unit it used manifold vacuum. However many cars used an assortment of vacuum delay valves and temperature controlled valves for emission control. Some MGs even came with no vacuum advance unit on the distributor at all.
Howard