I've been reading the Charles R. Morris book "Ford Y-Block a Performance History" and found the information about the Lincoln Y-Block interesting. I never saw one of these engines back in the day, probably because there weren't many Lincolns in my neighborhood.  I understand these engines were used in Turnpike Cruisers?   The port layout used in the Lincoln engines was similar to an FE.  My guess is Ford developed both engines separately and used knowledge gained from both when they made the FE?   I always thought the Y-Block was replaced because of limited displacement growth?  Why didn't they offer the Lincoln engine in all Fords?  Perhaps cost was an issue. Whatever the reason, the FE turned out well enough.