Elvis' 507 had a small block put in it.
https://www.bmw.com/en/automotive-li...507-elvis.html
And when BMW restored it, it sounds like they reinstalled a Chevrolet engine (though the picture shows a correct looking engine with front distributor)!
>So, instead of the 150 hp 3.2-litre V8 lightweight engine from Bavaria, they used a large-volume engine from Chevrolet.