Porsche Classic Fuel Tank - 1973 MFI connections

[Simonjjb]

I am working on a 1973 MFI car.

The fuel tank was absolutely shot - in fact when I tried to get one of the plugs out it sheared right off. I wanted a new tank this time and decided to try the new classic Porsche tank described as follows....(yes it comes grey not black) described as such...

Fuel tank, 62 litres
For all 911 F models from 1969–1973.
Part number: 91120190402
Manufactured using the optimised original tool and the original production techniques: 62-litre fuel tank.

Unfortunately the connections and the tank are not the same - maybe "optimized" was the key word with techniques..In any case, below are the new tank connections and also a picture of my old original tank. My new fuel sock connection will fit the large connection. Then I am left with 2 fixed short pipes, one smaller than the other. The pipes coming out of the tank are 8mm OD and the other 10.5mm OD.

Would welcome guidance on which pipe to use as the return line - and also how to block the extra pipe.

Thanks !

[edmayo]

On the original tank there were two large fittings, one used the filter sock and was supply for the engine. The other large was for a Webasto and also would have used the filter sock, but with smaller 8 mm outlet, engine outlet was 9 mm. Center was for fuel return. On the new tank of course the large will be for filter sock feed to engine. I would use the 8mm for return and block the large one. Is it threaded?

[Simonjjb]

Thanks very much Ed. Neither of the smaller lines have threads. Only the large Sock one.