Kent Fuller - of Top Fuel chassis fame - had a Porsche 4-cam Carrera motor in a Beetle, and an MGTF (or maybe TD?) with a BBC.
The MG was mind-boggling.

Generally, I prefer keeping engine swaps on-brand, but some argue that's not true hot-rodding, using the post-war scene as their reference.
Ain't worth arguing over, though - Gen 1 Hemis look good in '32 3-window Fords, right ?