Before WW2, Poland was spending much time and money in trying to develop a small twin-engine two seat fighter-bomber. The PSL 38 Wilk (Wolf) was supposed to provide Poland with an aircraft that could perform the duties of both fighter and dive-bomber. This aircraft was to be powered by two revolutionary engines, the PZL Foka (Seal) engine. The PZL Foka was an air-cooled inverted V-8 engine of 585 cu. inches that was supposed to provide 420 hp (variously 420hp, 450hp or 490hp) at 3800rpm continuously and 450hp at take off. The Foka only weighed 220kg. In tests, the engine only developed 320hp at 3800 rpm.
Foka never developed the hoped for horse-power and the Poles cancelled the PZL 38 Wilk and it's Foka engine in the spring of 1939. The Poles wasted millions of Zloty on the Wilk that probably should have been dedicated to a less ambitious fighter project.
Polish sources refer to the engine overheating because the cooling surface was too small and to cracked crankshaft housings because of engine balance issues.
At almost the same time as the Poles were pinning their hopes on the Foka powered Wilk, in Britain, Rolls Royce had developed a neat little air-cooled sleeve valve 24 cylinder X configuration engine called the "Exe" or Boreas. It had a displacement of 1,346 cu. in. and weighed 694kg. Exe was originally rated at 920hp @ 3800rpm and from all accounts was a reliable engine with room for development.
½ of an Exe would have been about 673 cu. inches, produced about 460hp and weighed about 350kg. Could Rolls Royce have made the Foka, or an engine similar to the Foka, work? ....well enough to power the PZL 38 Wilk?