Harley's also have radial engines, but there are only 2 cylinders.

 

That site is all over the place. It also lists that the S2000 has a 6-speed manual or 5-speed automatic.

 

and there have been V4 engines used in production passenger automobiles. My 1967 SAAB 96 had a V4 engine - actually the engine was borrowed from Ford of Europe (Taunus), and it replaced the ridiculous 3 cylinder 2 stroke corn popper engine.