In my misspent youth, I watched two guys install/hack an 1800 horsepower Allison V-1710 (V-12) form a decommissioned P-51 Mustang fighter, into a 1967 Ford Mustang.
An interesting endeavour, if somewhat foolhardy. I vaguely recall that "standard practice" back in the day was to put the V-12 on an industrial bandsaw and (sob) saw it in half to make a relatively lightweight 6 cylinder race car engine. I definitely recall seeing one such bandsaw with the two engine halves nearby. On a brighter note, I recently visited a facility in Florida and sat in a shop with what looked like 50+ Allisons, Merlins, and possibly other assorted V-12 engines lined up on the shelves, so at least someone is preserving and refurbishing them.