We’ve seen many V-8 Miata engine swaps, as well as I-4 and V-6 swaps.
But this one one is the king of them all: 2 (two!) V-8 engines, inline, and slaved together. You might call it a V-16, although technically it’s not.
The V-16 Miata was built by one Tony Hair, who used two relatively cheap “Chevy 350” engines. Why would anybody build such a thing? Answer: just ’cause. In the world of engine swaps, the question “why” is never asked. Once completed, some might call this the “ultimate” Miata. Keep in mind that as soon as something like this is built, somebody, somewhere, is going to start planning something even more outrageous. That is what the engine swap hobby is all about.
In the video you’ll note that, unfortunately, this is one Miata that is not suited to the autocross course :-)