have a 1974 164e which has 118k original miles on it and am trying to replace the gas tank. The original aluminum has some holes corroded in it. The only tanks I can find appear to be designed for an "in the tank" fuel pump. exactly the right shape, bolt right up, sending unit fits, just no side pickup for the external pump. did they build these things both ways? the Bosch oem pump is an external pump. Is there something I'm missing?