They don't have to leak, FE's, but I concur that many do. Something that still leaves me baffled, it ISN'T a given. Mine doesn't leak, and I'm not some hot shot mechanic OR someone who got lucky. I just took extaordinary care with all the sealing surfaces and took nothing for granted. Did extensive research right here on Club Cobra to be aware of what to look for.
Recently attended a car show, newly converted GT-500 Eleanor fastback there. Brand new Genesis block, alloy heads, polished everything, dual fours, awesome! $30,000 for the motor alone. Couldn't drive it, trailored in, bottom of the bell housing covered in
oil... WHAT is UP with THAT???? 30K and it leaks
oil? Unacceptable, but yeah, all to dang common.