This should have a "rope seal" These are sold a strip of seal that is straight, it must be fitted into the block and rear mains bearing cap according to the ford instructions. the grooves in the crank where the seal runs need to be cleaned of any muck there. They are notorious for leaking, if its just a weep, Id ignore it. BTW it a big job to change it, engine out sump off, crank out. The blocks can be modified for a lip seal, but this requires complete dissassembly of the engine.