Man, that was so fast... Almost like Usain Bolt !
You are right : In 1967, Scuderia Ferrari engineer Franco Rocchi built an experimental 65×50mm, 498 cc W3 engine, effectively a single crankpin module, in order to assess the potential for a 3-litre W18 Formula 1 engine. Although the engine developed 80 bhp at 11,000 rpm and 160 bhp per litre, the idea was abandoned. Subsequently in 1972 Formula 1 rules were changed to outlaw the use of engines with more than 12 cylinders. Rocchi used this module as the basis for a 3½ litre W12 engine for Life Racing Engines in 1988, although this was infamously unsuccessful.
Here we can see a 1943 W18 Tatra T955 aircooled engine in its full glory.
Well done again matt21.