A few months back I bought a 2nd hand RWD Zetec plenum chamber.
It needs new injector seals as the old ones are split and damaged but I'm not sure what the old ones are for. The seals that I have taken off the Zetec plenum are different and don't really fit.
Heres a picture of the seal I took out.

There are two sorts from the side fed style fuel rail. The mondeo ones into the plastic manifold and the escort ones into the alloy sandwich plate. One is bigger than the other, I can not remember what way around ??

The smaller ones gave an air leak on mine so I used the bigger ones.

Thanks big_wasa helpfull as always.