The Ford Mustang faced an identity crisis when it made the switch from its time-tested overhead-valve 5.0-liter V-8 to an entirely new DOHC “modular” eight-cylinder engine family in the mid-1990s.

So, you're mapping out a hot rod project—a "build," if you will—and you plan to use Ford's Coyote 5.0-liter engine as its motivator. Excellent! That's all well and good, especially if a Fox-body ...