Are there different stock heads? If so how can I identify them? I have a pair and am toying with idea of selling them, but thought I'd see if I can identify them first. Thanks for any help.
There are different heads, but as far as I know, a**** factory ones the choices were Iron and aluminum. The aluminum ones are are less common, and sometimes sought after by the "speed parts look" crowd. Overall demand for any of them is not huge, as there simply are not that many surviving Lincoln V12 engines out there. For exacting detail, you might call H&H Flatheads. They deal with these more regularly than I ever could. https://handhflatheads.com/
Good Luck. Not very many people actively re-building those engines at any given moment. In fact I would wager that my cousin Stumpy wouldn't even have to untie his shoes to count the number of people worldwide building a Lincoln Flathead V12.
Like I said in another thread, all of the Lincoln Continentals with dead V12s were George Hurst's inspiration to start making conversion mounts to replace them with Oldsmobile and Cadillac OHV V8s.
Try the Lincoln Zephyr Owners Club. People sell the heads all the time. Several dealers available in the cl***ifieds. https://www.lzoc.org/cl***ifieds