Hey Dave, Jim and Brian,
I got a little ahead of myself with the question about interchangeability. My error was not remembering that, unlike the SB Chevy, which I have read about the most and which remained the same up until the LTx/LSx engines, Ford has had several different families.
But my main curiosity was if there were any engines that Mercury and Lincoln designed in house that were as different from the Ford engines as the BOP engines were from the Chevy. Basically if FoMoCo ever went the "corporate engine" route the way GM did.
@ Brian: the link to the thread on the Y blocks was a good informative read, thank for that.
@ Jim: Thank you for the heads up. I did find more info on the MEL engine family, as well as the V12 you mentioned: "Lincoln-Zephyr V12 engine"
Its obvious I've got some serious reading ahead of me, so I did a quick search this morning and did find a nice breakdown of the Ford engine families: "Ford V-8 Engine Families--A Primer : eBay Guides"
For anyone reading this thread looking for more technical information, the wiki also has two good articles: "Ford engine specifications"
and "How to identify a Ford V8"
Thank you all so much for the help and pointing me in the right direction.