Just don't expect to see it in the 911.
Porsche's commitment to mid-engine sports cars was proved with the debuts of the 2020 718 Cayman GT4 and 718 Spyder. Both come powered by a newly developed naturally aspirated 4.0-liter flat-six generating 414 horsepower and 309 lb-ft of torque. This engine shares much of its design with the 992 911's twin-turbo 3.0-liter flat-six, so it should come as no surprise that some 911 enthusiasts are interested in seeing that new NA flat-six dropped into the 911's rear end. According to Road and Track, however, that'll never happen. But this doesn't mean the engine won't be used elsewhere.
Dr. Frank Walliser, chief engineer of the 718 and 911, admitted that "with (an) engineering effort you could (use the new engine in the 911). But it's a lot of changes… the throttle is in the wrong direction, the water connection is in the wrong direction." The bottom line is that even though this particular engine is cheaper to build than the 911 GT3's own NA 4.0-liter flat-six, it's simply not worth the engineering effort to make those modifications.
Furthermore, even if the conversion was done the outcome would still be an engine that'd be less powerful than the output of the Carrera S. Those who only want a naturally aspirated 992 will instead have to wait for the next 911 GT3.
That car will be powered by the same 4.0-liter from the Speedster revealed last spring. Fortunately, Walliser hinted that the GT4's 4.0-liter isn't done yet. Instead of the 911, it will likely be used in future 718s, that is, of course, before the model line goes all-electric.
Fortunately, the current 718 Cayman and Boxster are expected to remain on sale until 2023, so there's still plenty of time to utilize that new engine for additional high-performance and track-focused variants.